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Carstens L, Popp M, Keicher C, Hertrampf R, Weigner D, Meiering MS, Luippold G, Süssmuth SD, Beckmann CF, Wunder A, Grimm S. Effects of a single dose of amisulpride on functional brain changes during reward- and motivation-related processing using task-based fMRI in healthy subjects and patients with major depressive disorder - study protocol for a randomized clinical trial. Trials 2023; 24:761. [PMID: 38012795 PMCID: PMC10683198 DOI: 10.1186/s13063-023-07788-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND Anhedonia and other deficits in reward- and motivation-related processing in psychiatric patients, including patients with major depressive disorder (MDD), represent a high unmet medical need. Neurobiologically, these deficits in MDD patients are mainly associated with low dopamine function in a frontostriatal network. In this study, alterations in brain activation changes during reward processing and at rest in MDD patients compared with healthy subjects are explored and the effects of a single low dose of the dopamine D2 receptor antagonist amisulpride are investigated. METHODS This is a randomized, controlled, double-blind, single-dose, single-center parallel-group clinical trial to assess the effects of a single dose of amisulpride (100 mg) on blood-oxygenation-level-dependent (BOLD) responses during reward- and motivation-related processing in healthy subjects (n = 60) and MDD patients (n = 60). Using functional magnetic resonance imaging (fMRI), BOLD responses are assessed during the monetary incentive delay (MID) task (primary outcome). Exploratory outcomes include BOLD responses and behavioral measures during the MID task, instrumental learning task, effort-based decision-making task, social incentive delay task, and probabilistic reward task as well as changes in resting state functional connectivity and cerebral blood flow. DISCUSSION This study broadly covers all aspects of reward- and motivation-related processing as categorized by the National Institute of Mental Health Research Domain Criteria and is thereby an important step towards precision psychiatry. Results regarding the immediate effects of a dopaminergic drug on deficits in reward- and motivation-related processing not only have the potential to significantly broaden our understanding of underlying neurobiological processes but might eventually also pave the way for new treatment options. TRIAL REGISTRATION ClinicalTrials.gov NCT05347199. April 12, 2022.
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Affiliation(s)
| | - Margot Popp
- Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an Der Riss, Germany
| | | | | | | | | | - Gerd Luippold
- Clinical Development and Operations, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an Der Riss, Germany
| | - Sigurd D Süssmuth
- Medicine Therapeutic Area CNS-Retinopathies-Emerging Areas, Boehringer Ingelheim International GmbH, Biberach an Der Riss, Germany
| | - Christian F Beckmann
- Donders Institute, Centre for Medical Neuroscience, Radboud University Medical Centre, Nijmegen, Netherlands
- Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
- SBGneuro Ltd, Littlemore, Oxford, UK
| | - Andreas Wunder
- Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an Der Riss, Germany
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Zhang Q, Delessa CT, Augustin R, Bakhti M, Colldén G, Drucker DJ, Feuchtinger A, Caceres CG, Grandl G, Harger A, Herzig S, Hofmann S, Holleman CL, Jastroch M, Keipert S, Kleinert M, Knerr PJ, Kulaj K, Legutko B, Lickert H, Liu X, Luippold G, Lutter D, Malogajski E, Medina MT, Mowery SA, Blutke A, Perez-Tilve D, Salinno C, Sehrer L, DiMarchi RD, Tschöp MH, Stemmer K, Finan B, Wolfrum C, Müller TD. The glucose-dependent insulinotropic polypeptide (GIP) regulates body weight and food intake via CNS-GIPR signaling. Cell Metab 2021; 33:833-844.e5. [PMID: 33571454 PMCID: PMC8035082 DOI: 10.1016/j.cmet.2021.01.015] [Citation(s) in RCA: 115] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 12/04/2020] [Accepted: 01/14/2021] [Indexed: 01/04/2023]
Abstract
Uncertainty exists as to whether the glucose-dependent insulinotropic polypeptide receptor (GIPR) should be activated or inhibited for the treatment of obesity. Gipr was recently demonstrated in hypothalamic feeding centers, but the physiological relevance of CNS Gipr remains unknown. Here we show that HFD-fed CNS-Gipr KO mice and humanized (h)GIPR knockin mice with CNS-hGIPR deletion show decreased body weight and improved glucose metabolism. In DIO mice, acute central and peripheral administration of acyl-GIP increases cFos neuronal activity in hypothalamic feeding centers, and this coincides with decreased body weight and food intake and improved glucose handling. Chronic central and peripheral administration of acyl-GIP lowers body weight and food intake in wild-type mice, but shows blunted/absent efficacy in CNS-Gipr KO mice. Also, the superior metabolic effect of GLP-1/GIP co-agonism relative to GLP-1 is extinguished in CNS-Gipr KO mice. Our data hence establish a key role of CNS Gipr for control of energy metabolism.
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Affiliation(s)
- Qian Zhang
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Challa Tenagne Delessa
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology (D-HEST), ETH Zürich, Zurich, Switzerland
| | - Robert Augustin
- Cardiometabolic Diseases Research Department, Boehringer Ingelheim Pharma GmbH and Co., KG, Biberach/Riss, Germany
| | - Mostafa Bakhti
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Gustav Colldén
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Daniel J Drucker
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Annette Feuchtinger
- Research Unit Analytical Pathology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Cristina Garcia Caceres
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Gerald Grandl
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Alexandra Harger
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Stephan Herzig
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Center Munich, Neuherberg, Germany; Molecular Metabolic Control, Technical University of Munich, Munich, Germany
| | - Susanna Hofmann
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Medizinische Klinik und Poliklinik IV, Klinikum der LMU, München, Germany
| | - Cassie Lynn Holleman
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Martin Jastroch
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
| | - Susanne Keipert
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
| | - Maximilian Kleinert
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Patrick J Knerr
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN 46241, USA
| | - Konxhe Kulaj
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Beata Legutko
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Heiko Lickert
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Technische Universität München, School of Medicine, Klinikum Rechts der Isar, 81675 München, Germany
| | - Xue Liu
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Gerd Luippold
- Cardiometabolic Diseases Research Department, Boehringer Ingelheim Pharma GmbH and Co., KG, Biberach/Riss, Germany
| | - Dominik Lutter
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Emilija Malogajski
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Marta Tarquis Medina
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Technische Universität München, School of Medicine, Klinikum Rechts der Isar, 81675 München, Germany
| | | | - Andreas Blutke
- Research Unit Analytical Pathology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Diego Perez-Tilve
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Ciro Salinno
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Technische Universität München, School of Medicine, Klinikum Rechts der Isar, 81675 München, Germany
| | - Laura Sehrer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | | | - Matthias H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Helmholtz Zentrum München, Neuherberg, Germany; Technische Universität München, München, Germany
| | - Kerstin Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Brian Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN 46241, USA
| | - Christian Wolfrum
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology (D-HEST), ETH Zürich, Zurich, Switzerland
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, 72076 Tübingen, Germany.
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Luippold G, Mark M, Klein T, Amann K, Daniel C. Differences in kidney-specific DPP-4 inhibition by linagliptin and sitagliptin. Diabetes Res Clin Pract 2018; 143:199-203. [PMID: 30031047 DOI: 10.1016/j.diabres.2018.07.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/05/2018] [Accepted: 07/03/2018] [Indexed: 12/13/2022]
Abstract
The two dipeptidyl peptidase (DPP)-4 inhibitors, linagliptin and sitagliptin, were shown to exert different binding kinetics in vitro. Twenty-four hours after oral dosing particularly in vivo inhibition of renal-specific DPP-4 activity was more sustained in Sprague Dawley rats after exposure to linagliptin than it was after sitagliptin.
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Affiliation(s)
- Gerd Luippold
- Boehringer Ingelheim Pharma GmbH & Co. KG, CardioMetabolic Diseases, Biberach, Germany
| | - Michael Mark
- Boehringer Ingelheim Pharma GmbH & Co. KG, CardioMetabolic Diseases, Biberach, Germany
| | - Thomas Klein
- Boehringer Ingelheim Pharma GmbH & Co. KG, CardioMetabolic Diseases, Biberach, Germany
| | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Christoph Daniel
- Department of Nephropathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
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Grempler R, Wolff M, Simon E, Schmid R, Eisele C, Rieber K, Fischer E, Mettel S, Gabrielyan O, Delic D, Luippold G, Redeman N. Discovery and translation of a target engagement marker for AMP-activated protein kinase (AMPK). PLoS One 2018; 13:e0197849. [PMID: 29799853 PMCID: PMC5969744 DOI: 10.1371/journal.pone.0197849] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 05/09/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Activation of the AMP-activated protein kinase (AMPK) is an attractive approach for the treatment of type 2 diabetes. AMPK activation reduces glucose levels in animal models of type 2 diabetes by increasing glucose uptake in skeletal muscles and reducing hepatic glucose production. Furthermore, AMPK activation ameliorates hepatic steatosis in animal models. For the clinical development of AMPK activators it is essential to have a reliable target engagement marker for appropriate dose finding and to support proof of clinical principle. While the activation of AMPK by quantification of the phosphorylation of AMPK at Thr172 in target tissues can be assessed pre-clinically, this is not feasible in clinical studies. Therefore, we attempted to identify and translate a peripheral target engagement biomarker downstream of AMPK activation for clinical use in blood samples. METHODS For pharmacological activation of AMPK, two AMPK activators were synthesized (compound 1 and 2). A compound with structural similarities but no pharmacological effect on AMPK phosphorylation was synthesized as negative control (compound 3). Whole blood from healthy volunteers was incubated with an AMPK activator for up to 6 hours and mRNA sequencing was performed. Additionally, human PBMCs were isolated to evaluate Thr172-phosphorylation of AMPK in Western blots. In order to enable identification of translatable biomarker candidates, blood samples from HanWistar rats treated for two weeks with an AMPK activator were also subjected to mRNA sequencing. Furthermore, concentration-response curves for four biomarker candidates were recorded in human blood samples using Nanostring nCounter technology. Finally, ZDF rats were treated with increasing doses of compound 2 for five weeks to investigate the glucose-lowering efficacy. To investigate changes of mRNA expression of two selected biomarker candidates in this ZDF rat study, qRT-PCR was performed. RESULTS Pharmacological activation of AMPK in human PBMCs revealed an increase in Thr172-phosphorylation of AMPK, confirming target engagement in these blood cells. RNA sequencing of human blood samples identified 608 deregulated genes after AMPK activation. Additionally, AMPK activation led to deregulation of 367 genes in whole blood from HanWistar rats which mapped to the respective human genes. 22 genes out of the intersection of genes deregulated in both species are proposed as potential translatable target engagement biomarker candidates. The most prominent genes were transmembrane glycoprotein NMB (GPNMB, osteoactivin), calcium-binding protein A9 (S100A9), peptidoglycan recognition protein (PGLYRP1) and Ras homolog gene family, member B (RHOB). Specificity for AMPK was shown by testing inactive compound 3 in HanWistar rats. The exposure-effect relationship for GPNMB was investigated in a subchronic study in diabetic ZDF rats. GPNMB showed a dose-dependent up-regulation both acutely and after subchronic dosing. GPNMB up-regulation correlated with an increased Thr172-phosphorylation of AMPK in liver and quadriceps muscle in rats. CONCLUSION GPNMB has been identified as a translatable target engagement biomarker for use in clinical studies.
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Affiliation(s)
- Rolf Grempler
- Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
- * E-mail:
| | - Michael Wolff
- Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Eric Simon
- Department of Target Discovery Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Ramona Schmid
- Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Claudia Eisele
- Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Kathrin Rieber
- Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Elke Fischer
- Department of Cardio Metabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Sonja Mettel
- Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Ogsen Gabrielyan
- Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Denis Delic
- Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Gerd Luippold
- Department of Cardio Metabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Norbert Redeman
- Department of Cardio Metabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
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Perdikari A, Kulenkampff E, Rudigier C, Neubauer H, Luippold G, Redemann N, Wolfrum C. A high-throughput, image-based screen to identify kinases involved in brown adipocyte development. Sci Signal 2017; 10:10/466/eaaf5357. [DOI: 10.1126/scisignal.aaf5357] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Uhrig-Schmidt S, Geiger M, Luippold G, Birk G, Mennerich D, Neubauer H, Grimm D, Wolfrum C, Kreuz S. Gene delivery to adipose tissue using transcriptionally targeted rAAV8 vectors. PLoS One 2014; 9:e116288. [PMID: 25551639 PMCID: PMC4281237 DOI: 10.1371/journal.pone.0116288] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 12/08/2014] [Indexed: 02/02/2023] Open
Abstract
In recent years, the increasing prevalence of obesity and obesity-related co-morbidities fostered intensive research in the field of adipose tissue biology. To further unravel molecular mechanisms of adipose tissue function, genetic tools enabling functional studies in vitro and in vivo are essential. While the use of transgenic animals is well established, attempts using viral and non-viral vectors to genetically modify adipocytes in vivo are rare. Therefore, we here characterized recombinant Adeno-associated virus (rAAV) vectors regarding their potency as gene transfer vehicles for adipose tissue. Our results demonstrate that a single dose of systemically applied rAAV8-CMV-eGFP can give rise to remarkable transgene expression in murine adipose tissues. Upon transcriptional targeting of the rAAV8 vector to adipocytes using a 2.2 kb fragment of the murine adiponectin (mAP2.2) promoter, eGFP expression was significantly decreased in off-target tissues while efficient transduction was maintained in subcutaneous and visceral fat depots. Moreover, rAAV8-mAP2.2-mediated expression of perilipin A – a lipid-droplet-associated protein – resulted in significant changes in metabolic parameters only three weeks post vector administration. Taken together, our findings indicate that rAAV vector technology is applicable as a flexible tool to genetically modify adipocytes for functional proof-of-concept studies and the assessment of putative therapeutic targets in vivo.
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Affiliation(s)
| | - Matthias Geiger
- Swiss Federal Institute of Technology, ETH Zurich, SLA C92, Institute of Food Nutrition and Health, Schwerzenbach, Switzerland
| | - Gerd Luippold
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Gerald Birk
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Detlev Mennerich
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Heike Neubauer
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Dirk Grimm
- Centre for Infectious Diseases/Virology, Heidelberg University Hospital and Cluster of Excellence CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, Heidelberg, Germany
| | - Christian Wolfrum
- Swiss Federal Institute of Technology, ETH Zurich, SLA C92, Institute of Food Nutrition and Health, Schwerzenbach, Switzerland
| | - Sebastian Kreuz
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
- * E-mail:
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Trieselmann T, Wagner H, Fuchs K, Hamprecht D, Berta D, Cremonesi P, Streicher R, Luippold G, Volz A, Markert M, Nar H. Potent cholesteryl ester transfer protein inhibitors of reduced lipophilicity: 1,1'-spiro-substituted hexahydrofuroquinoline derivatives. J Med Chem 2014; 57:8766-76. [PMID: 25265559 DOI: 10.1021/jm500431d] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A series of 1,1'-spiro-substituted hexahydrofuroquinoline derivatives exhibiting potent cholesteryl ester transfer protein (CETP) inhibition at reduced lipophilicity was identified. A focused structure-activity relationship (SAR) exploration led to the potent and comparatively polar CETP inhibitor 26 showing robust high density lipoprotein-cholesterol (HDL-C) elevation and low density lipoprotein-cholesterol (LDL-C) reduction in transgenic hCETP/hApoB-100 mice. Compound 26 was also shown to positively differentiate from highly lipophilic CETP inhibitors in its complete elimination from fat tissue in hCETP transgenic mice as evident within 21 days after cessation of treatment. In addition, compound 26 showed no significant effects on aldosterone secretion from H295R cells, as well as no significant effects on blood pressure and electrocardiogram parameters in telemetrized cynomolgus monkeys.
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Affiliation(s)
- Thomas Trieselmann
- Departments of Medicinal Chemistry, §Cardiometabolic Diseases, ⊥Drug Discovery Support, and ∥Lead Identification, Boehringer Ingelheim Pharma GmbH & Co. KG , Birkendorfer Strasse 65, 88397 Biberach an der Riss, Germany
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Schiele F, Park J, Redemann N, Luippold G, Nar H. An Antibody against the C-Terminal Domain of PCSK9 Lowers LDL Cholesterol Levels In Vivo. J Mol Biol 2014; 426:843-52. [DOI: 10.1016/j.jmb.2013.11.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 11/11/2013] [Accepted: 11/12/2013] [Indexed: 10/26/2022]
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Luippold G, Klein T, Mark M, Grempler R. Empagliflozin, a novel potent and selective SGLT-2 inhibitor, improves glycaemic control alone and in combination with insulin in streptozotocin-induced diabetic rats, a model of type 1 diabetes mellitus. Diabetes Obes Metab 2012; 14:601-7. [PMID: 22268612 DOI: 10.1111/j.1463-1326.2012.01569.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
AIM Sodium glucose cotransporter-2 (SGLT-2) is key to reabsorption of glucose in the kidney. SGLT-2 inhibitors are in clinical development for treatment of type 2 diabetes mellitus (T2DM). The mechanism may be of value also in the treatment of type 1 diabetes mellitus (T1DM). This study investigated effects of the SGLT-2 inhibitor, empagliflozin, alone and in combination with insulin, on glucose homeostasis in an animal model of T1DM. METHODS Sprague-Dawley rats were administered a single intraperitoneal injection of streptozotocin (STZ; 60 mg/kg). Acutely, STZ rats received two doses of insulin glargine with or without empagliflozin, and blood glucose was measured. In a subchronic study, STZ rats received empagliflozin alone, one or two insulin-releasing implants or a combination of one implant and empagliflozin over 28 days; blood glucose and HbA(1c) were measured. RESULTS In the acute setting, empagliflozin in combination with 1.5 IU insulin induced a similar glucose-lowering effect as 6 IU insulin. Both interventions were more efficacious than monotherapy with 1.5 IU insulin. In the subchronic study, 12-h blood glucose profile on day 28 in the combination group was lower than with one implant, and similar to two implants. Plasma HbA(1c) was improved in the combination group and in animals with two implants. CONCLUSIONS Empagliflozin reduced blood glucose levels in a T1DM animal model. Empagliflozin combined with low-dose insulin showed comparable glucose-lowering efficacy to treatment with high-dose insulin. Our data suggest that empagliflozin is an efficacious adjunctive-to-insulin therapy with the clinical potential for the treatment of T1DM.
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Affiliation(s)
- G Luippold
- Department of CardioMetabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, Biberach an der Riss, Germany.
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Suhre K, Römisch-Margl W, de Angelis MH, Adamski J, Luippold G, Augustin R. Identification of a potential biomarker for FABP4 inhibition: the power of lipidomics in preclinical drug testing. ACTA ACUST UNITED AC 2011; 16:467-75. [PMID: 21543640 DOI: 10.1177/1087057111402200] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The fatty acid binding protein 4 (FABP4) belongs to the family of lipid chaperones that control intracellular fluxes and compartmentalization of their respective ligands (e.g., fatty acids). FABP4, which is almost exclusively expressed in adipocytes and macrophages, contributes to the development of insulin resistance and atherosclerosis in mice. Lack of FABP4 protects against the development of insulin resistance associated with genetic or diet-induced obesity in mice. Furthermore, total or macrophage-specific FABP4 deficiency is protective against atherosclerosis in apolipoprotein E-deficient mice. The FABP4 small-molecule inhibitor BMS309403 has demonstrated efficacy in mouse models for type 2 diabetes mellitus and atherosclerosis, resembling phenotypes of mice with FABP4 deficiency. However, despite the therapeutically attractive long-term effects of FABP4 inhibition, an acute biomarker for drug action is lacking. The authors applied mass spectrometry lipidomics analysis to in vitro and in vivo (plasma and adipose tissue) samples upon inhibitor treatment. They report the identification of a potential biomarker for acute in vivo FABP4 inhibition that is applicable for further investigations and can be implemented in simple and fast-flow injection mass spectrometry assays. In addition, this approach can be considered a proof-of-principle study that can be applied to other lipid-pathway targeting mechanisms.
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Affiliation(s)
- Karsten Suhre
- 1Institute for Bioinformatics and Systems Biology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
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Stüer C, Ikeda T, Stoffel M, Luippold G, Sakowitz O, Schaller K, Meyer B. NOREPINEPHRINE AND CEREBRAL BLOOD FLOW REGULATION IN PATIENTS WITH ARTERIOVENOUS MALFORMATIONS. Neurosurgery 2008. [DOI: 10.1227/01.neu.0000317275.65174.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Stüer C, Ikeda T, Stoffel M, Luippold G, Sakowitz O, Schaller K, Meyer B. NOREPINEPHRINE AND CEREBRAL BLOOD FLOW REGULATION IN PATIENTS WITH ARTERIOVENOUS MALFORMATIONS. Neurosurgery 2008; 62:1254-60; discussion 1260-1. [DOI: 10.1227/01.neu.0000333296.41813.74] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Staudacher T, Pech B, Tappe M, Gross G, Mühlbauer B, Luippold G. Arterial blood pressure and renal sodium excretion in dopamine D3 receptor knockout mice. Hypertens Res 2007; 30:93-101. [PMID: 17460376 DOI: 10.1291/hypres.30.93] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alterations in the dopaminergic system may contribute to the development of hypertension. Recently, it has been reported that pentobarbital-anesthetized mice with deficient dopamine D(3) receptors showed renin-dependent elevation in blood pressure. In a series of experiments, we evaluated the contribution of the dopamine D(3) receptor to the renal sodium excretion and arterial blood pressure behavior in conscious as well as anesthetized dopamine D(3) receptor knockout (-/-) mice. The blood pressure measuring study was designed as a cross-over trial to investigate the influence of different sodium loads. The animals were fed a normal salt diet (0.6% NaCl, NS) for 1 week and afterwards a low (0.2% NaCl, LS) or a high salt diet (4.6% NaCl, HS) for 2 weeks. After the third week, the animals were switched to the corresponding protocol. Systolic blood pressure in conscious (-/-) mice measured by tail-cuff plethysmography was not different from that of wild-type (+/+) animals, irrespective of the time course or the salt diet. In another experiment, challenge of an acute sodium loading per gavage in conscious D(3) receptor (-/-) and (+/+) animals on HS or NS diet did not show significant differences in renal sodium excretion between the two genotypes. Additionally, animals were fed an NS diet for 1 week and an HS diet for another week. As expected, sodium excretion significantly increased after the change from the NS to the HS diet. A slightly lower urinary sodium excretion was observed when comparing D(3) receptor (-/-) mice to their corresponding (+/+) mice, both on an HS diet. Clearance experiments with anesthetized D(3) receptor (-/-) and (+/+) mice were performed to investigate the renal sodium excretion capacity, when exposed to a moderate volume expansion (VE). Urinary sodium excretion increased in response to the VE; however, no difference were observed between the two genotypes. Taking these results together, we conclude that in the present animal model renal dopamine D(3) receptors are not significantly involved in the regulation of blood pressure associated with a deficiency in renal sodium elimination.
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Affiliation(s)
- Torsten Staudacher
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Tübingen, Germany
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Pfeil K, Staudacher T, Luippold G. Effect of L-Dopa Decarboxylase Inhibitor Benserazide on Renal Function in Streptozotocin-Diabetic Rats. Kidney Blood Press Res 2006; 29:43-7. [PMID: 16636577 DOI: 10.1159/000092849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Accepted: 12/22/2005] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND/AIMS Benserazide (BZD), an inhibitor of the dopamine synthesis, abolished the increase in glomerular filtration rate (GFR) following the infusion of a mixed amino acid solution. These results reveal endogenous dopamine as a mediator in the renal response to amino acids. The aim of the present study was to evaluate whether dopamine is also involved in the regulation of glomerular hyperfiltration during the early state of diabetes mellitus (DM). METHODS Male Sprague-Dawley rats were injected with a single dose of streptozotocin (60 mg/kg i.p.) for induction of experimental DM (n = 7-8/group). Age-matched non-diabetic animals, injected with citrate buffer, served as controls (CON, n = 8/group). Clearance experiments were performed 2 weeks after induction of DM in thiopental-anesthetized rats (80 mg/kg i.p.), which were continuously infused either with BZD (30 microg/min/kg) or vehicle (VHC). RESULTS Mean arterial blood pressure was around 110 mm Hg and did not significantly differ among the groups. GFR was 0.95 +/- 0.02 ml/min/100 g b.w. in VHC-treated CON. BZD treatment did not significantly change GFR in the CON group (0.92 +/- 0.06 ml/min/100 g b.w.). As expected, glomerular hyperfiltration was observed in diabetic rats infused with VHC (1.24 +/- 0.08 ml/min/100 g b.w.). Treatment with BZD significantly reduced the diabetes-induced increase in GFR to control levels (0.95 +/- 0.05 ml/min/100 g b.w.). CONCLUSION Our results show that the inhibition of dopamine synthesis prevented the increase in GFR due to diabetic conditions, indicating that endogenous dopamine is involved in the regulation of DM-induced changes in renal hemodynamics.
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Affiliation(s)
- Katrin Pfeil
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Tübingen, Tübingen, Germany
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15
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Luippold G, Osswald H. [Economic aspects of treatment with diuretics]. Pharm Unserer Zeit 2006; 35:346-52. [PMID: 16886511 DOI: 10.1002/pauz.200600182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Affiliation(s)
- Gerd Luippold
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Tübingen.
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Luippold G, Pech B, Schneider S, Drescher K, Müller R, Gross G, Mühlbauer B. Absence of amino acid-induced glomerular hyperfiltration in dopamine D3 receptor knockout mice. Naunyn Schmiedebergs Arch Pharmacol 2005; 372:284-90. [PMID: 16372190 DOI: 10.1007/s00210-005-0020-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Accepted: 10/17/2005] [Indexed: 11/29/2022]
Abstract
Pharmacological inhibition of receptors of the dopamine D2-like family has been shown to abolish the glomerular hyperfiltration in response to amino acids. To further discriminate between the receptor subtypes within the D2-like family, we investigated the effects of amino acid infusion on renal function in dopamine D3 receptor knockout (-/-) mice. In clearance experiments pentobarbital-anesthetized D3 receptor (-/-) and wild-type (+/+) mice were infused with Ringer solution at baseline, followed by a continuous infusion of mixed amino acids (10%). Baseline glomerular filtration rate (GFR), assessed by renal clearance of [3H]-inulin, was the same in D3 receptor (-/-) mice (0.56+/-0.08 ml/min per g kidney weight) and wild-type animals (0.56+/-0.04 ml/min per g kw). During infusion of amino acids, GFR was significantly elevated by 50% in D3 receptor (+/+) mice. In contrast, this amino acid-induced response of GFR was abolished in D3 receptor (-/-) mice. Baseline urinary water and sodium excretion was not significantly different in both groups of mice. As observed in GFR, these renal excretory parameters were significantly elevated during amino acid infusion in D3 receptor (+/+) but not in D3 receptor (-/-) mice. Time controls, constantly infused with Ringer solution, did not show significant changes in GFR, renal water or sodium excretion during the entire experiment, indicating stable experimental conditions. Taken together, the data underline the involvement of dopamine D2-like receptors in the renal response to amino acid infusion and, in addition, attribute this effect to the dopamine D3 receptor subtype.
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Affiliation(s)
- Gerd Luippold
- Department of Pharmacology, University of Tübingen, Wilhelmstrasse 56, 72074, Tübingen, Germany.
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17
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Luippold G, Beilharz M, Wehrmann M, Unger L, Gross G, Mühlbauer B. Effect of dopamine D3 receptor blockade on renal function and glomerular size in diabetic rats. Naunyn Schmiedebergs Arch Pharmacol 2005; 371:420-7. [PMID: 15887004 DOI: 10.1007/s00210-005-1030-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Accepted: 01/28/2005] [Indexed: 01/11/2023]
Abstract
Dopamine D2-like receptors, including D2, D3, and D4 receptors, are involved in the regulation of glomerular hyperfiltration due to diabetes mellitus. These hemodynamic alterations represent a risk factor for the later development of diabetic nephropathy. The aim of the present study was to determine whether the D3 receptor subtype modulates the diabetes-induced increase in glomerular filtration rate (GFR) in rats. Renal function was studied in Sprague-Dawley rats 14 days after induction of a moderate diabetes mellitus (DM) by streptozotocin and in non-diabetic controls (CON). Rats were orally treated either with the peripherally acting, selective dopamine D3 receptor antagonist BSF 135170 (BSF, 10 mg/kg per day for 2 weeks) or with vehicle (VHC). Perfusion-fixed kidneys were used for estimation of glomerular volume. In conscious rats, which were treated with BSF, the DM-induced increase in fluid intake, urinary output, and renal sodium excretion was significantly less pronounced than in the vehicle group (DM-VHC). In the clearance experiments, GFR in CON was about 0.84+/-0.04 ml/min per 100 g body weight. The DM-VHC group presented a significant glomerular hyperfiltration (1.09+/-0.04 ml/min per 100 g body weight). Treatment with BSF significantly lowered GFR towards levels of CON. The estimated glomerular volume was 0.73+/-0.03 x 10(6) microm3 in the CON-VHC group and 0.86+/-0.04 x 10(6) microm3 in the DM-VHC animals. Interestingly, treatment with BSF decreased the glomerular volume in both groups. Irrespective of BSF treatment, kidney wet weight related to body weight was about 36% higher in DM animals compared with CON animals. We conclude that dopamine D3 receptors represent a target for the modulation of diabetes-induced glomerular hyperfiltration. Therefore, the results encourage the testing of the possible beneficial effects of long-term D3 receptor blockade on the development of diabetic nephropathy.
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Affiliation(s)
- Gerd Luippold
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Tübingen, Wilhelmstrasse 56, 72074 Tübingen, Germany,
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Abstract
The aim of the present study was to evaluate several long-acting insulin preparations for their ability to normalize the blood glucose profile of rats and mice with streptozocin-induced diabetes mellitus. The single injection of a long-acting zinc insulin (CAS 8049-62-5) suspension or insulin glargine (CAS 160337-95-1) in both species induced a steep to moderate fall in blood glucose concentration. Blood glucose was then normalized for 2-3 h, until 3 h after insulin injection blood glucose concentration tended towards levels before insulin application. In contrast, implants produced with a mixture of human insulin and palmitic acid micro-crystals normalized blood glucose profile over 24 h in both species at least 30 days after implantation. Therefore, these implants with a sustained release of insulin are suitable to control the blood glucose in diabetic rats and mice.
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Affiliation(s)
- Swetlana Schneider
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Tübingen, Tübingen, Germany
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Nürnberger A, Räbiger M, Mack A, Diaz J, Sokoloff P, Mühlbauer B, Luippold G. Subapical localization of the dopamine D3 receptor in proximal tubules of the rat kidney. J Histochem Cytochem 2004; 52:1647-55. [PMID: 15557219 DOI: 10.1369/jhc.4a6359.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The dopamine D3 receptor (D3R), intensively studied in neuroscience, also plays an important role in the regulation of renal and cardiovascular function. In contrast to functional findings, less information is available on its localization in the kidney. Neither RT-PCR studies nor radioligand binding assays are suitable to selectively determine the distribution of renal D3R at the level of cellular or even subcellular structures. We studied the renal D3R distribution in Sprague-Dawley rats by a polyclonal antiserum directed against an epitope in the third intracytoplasmic loop. D3R immunoreactivity was detected by indirect immunofluorescence and confocal laser scanning microscopy. D3R staining was confined to the renal cortex and occurred in proximal convoluted tubules near or in direct connection with the urinary pole of the glomeruli. The fluorescent spots were restricted to the subapical portion of the proximal tubular cells. Double staining with the F-actin marker phalloidin revealed a localization of the D3R below the brush border region. However, staining by anti-beta1/beta2-adaptins, recognizing clathrin-coated compartments, did not correspond to the distribution of the D3R signal. This is the first description of a D3R accumulation in a cytoplasmic pool in the kidney, probably corresponding to a recycling mechanism or storage compartment.
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Affiliation(s)
- Asja Nürnberger
- Dept. of Pharmacology and Toxicology, Faculty of Medicine, University of Tübingen, Wilhelmstr. 56, D-72074 Tübingen, Germany
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Abstract
BACKGROUND The increase in glomerular filtration rate (GFR) induced by amino acid infusion is attenuated in rats with chronic renal denervation. The aim of the present study was to investigate whether renal denervation abrogates glomerular hyperfiltration occurring in the early state of diabetes mellitus. METHODS Sprague-Dawley rats were subjected to bilateral renal denervation before induction of diabetes mellitus (DM) by streptozotocin. Clearance experiments were performed 2 weeks after onset of moderate DM. Glomerular volume was estimated following paraformaldehyde fixation in rat kidney slices from measurement of cross-sectional area of Bowman's capsule. RESULTS GFR in non-diabetic rats with intact nerves (CON-INN) was 0.82+/-0.03 ml.min(-1).100 g(-1) body weight. Diabetic animals with innervated kidneys presented a significant glomerular hyperfiltration (1.13+/-0.03 ml.min(-1).100 g(-1) body weight), while renal denervation in diabetic rats lowered GFR towards levels of CON-INN (0.88+/-0.03 ml.min(-1).100 g(-1) body weight). Estimated glomerular volume amounted to 0.69+/-0.03.10(6) micro m(3) in the CON-INN group and was significantly higher in diabetic animals with intact renal nerves (0.86+/-0.04.10(6) microm(3)). Interestingly, renal denervation prevented the glomerular enlargement due to DM. CONCLUSIONS Renal nerves appear to be significantly involved in the mediation of glomerular hyperfiltration in experimental DM. If the kidney is prevented from sympathetic nerve stimulation, structural changes due to early diabetic nephropathy, i.e. glomerular enlargement, are abolished.
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Affiliation(s)
- Gerd Luippold
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Tübingen, Tübingen, Germany.
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Birk C, Richter K, Huang DY, Piesch C, Luippold G, Vallon V. The salt paradox of the early diabetic kidney is independent of renal innervation. Kidney Blood Press Res 2004; 26:344-50. [PMID: 14610339 DOI: 10.1159/000073941] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2003] [Indexed: 11/19/2022] Open
Abstract
Glomerular filtration rate (GFR) is inversely and thus paradoxically related to dietary NaCl intake in rats and patients with early type 1 diabetes mellitus (DM). Enhanced sensitivity of proximal reabsorption to NaCl diet inducing secondary adaptations in GFR through actions of tubuloglomerular feedback causes this salt paradox. We studied the role of renal nerves for the salt paradox in rats with streptozotocin (STZ)-induced DM since a regulatory influence of renal nerves on proximal reabsorption is well established. The left kidney (LK) was denervated before induction of STZ-DM. Subsequently, the normal diet was continued or a low NaCl diet was initiated and 1 week later animals were prepared for clearance experiments under anesthesia including ureter catheterization to measure GFR for each kidney. In diabetic rats, the right innervated as well as the left denervated kidney showed higher values for GFR and kidney weight in animals on a low versus a normal NaCl diet indicating that the salt paradox occurs independent of renal innervation. In addition, evidence is provided that the renal nerves of non-diabetic rats do not contribute to renal Na(+) retention during dietary NaCl restriction but modulate renal hemodynamics and kidney weight under these conditions.
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Affiliation(s)
- C Birk
- Institute of Pharmacology and Toxicology, University of Tübingen, Tübingen, Germany
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Kivistö KT, Zukunft J, Hofmann U, Niemi M, Rekersbrink S, Schneider S, Luippold G, Schwab M, Eichelbaum M, Fromm MF. Characterisation of cerivastatin as a P-glycoprotein substrate: studies in P-glycoprotein-expressing cell monolayers and mdr1a/b knock-out mice. Naunyn Schmiedebergs Arch Pharmacol 2004; 370:124-30. [PMID: 15322734 DOI: 10.1007/s00210-004-0948-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2004] [Accepted: 05/26/2004] [Indexed: 11/30/2022]
Abstract
The aim of this study was to characterise the role of the efflux transporter P-glycoprotein in the disposition of cerivastatin. We investigated directional transport characteristics of [14C]cerivastatin across cell monolayers expressing P-glycoprotein (Caco-2 and L-MDR1) and disposition of cerivastatin in mice with disrupted mdr1a and mdr1b genes. The mice were given orally 1 mg/kg cerivastatin and plasma and tissue samples for analysis of cerivastatin were obtained 10, 20, or 30 min after drug administration. Four knock-out mice and four wild-type mice were studied at each time point. In addition, the hypothesis that gemfibrozil-mediated inhibition of P-glycoprotein contributes to the interaction between gemfibrozil and cerivastatin was tested in Caco-2 cells. The apparent permeability coefficient (P(app)) value for the basal-to-apical transport of cerivastatin in Caco-2 and L-MDR1 cell monolayers was 2.4 times (P<0.001) and 3.8 times (P<0.001) as high as the apical-to-basal P(app) value respectively. The P-glycoprotein inhibitor PSC-833 (1 microM) inhibited the net basal-to-apical transport of cerivastatin in Caco-2 monolayers by 35% (P<0.01) and the MRP inhibitor MK-571 (10 microM) by 50% (P<0.01). At concentrations up to 250 microM, gemfibrozil showed no significant effects on the net transport of cerivastatin in Caco-2 cells. The concentration of cerivastatin in the brain at 30 min was 3.1 times higher in the knock-out mice than in the wild-type mice (P<0.05). The brain-to-plasma cerivastatin concentration ratio at 20 min and 30 min was 2.1 (P<0.05) and 3.6 times (P<0.05) higher respectively in the knock-out animals compared with the wild-type animals. Collectively, these results indicate that cerivastatin is a P-glycoprotein substrate, although other transporters probably contribute to cerivastatin transport in humans. As several statins are P-glycoprotein substrates, beneficial as well as adverse effects of the statins might be affected by interindividual differences in P-glycoprotein expression or function caused by, e.g., the MDR1 polymorphism.
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Affiliation(s)
- Kari T Kivistö
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Auerbachstrasse 112, 70376 Stuttgart, Germany.
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Luippold G, Piesch C, Osswald H, Mühlbauer B. Dopamine D3 receptor mRNA and renal response to D3 receptor activation in spontaneously hypertensive rats. Hypertens Res 2004; 26:855-61. [PMID: 14621190 DOI: 10.1291/hypres.26.855] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Defective dopamine receptors may be involved in the development of hypertension. Recently, it has been shown that gene expression and function of the renal dopamine D3 receptor is impaired in salt-sensitive Dahl rats, a model of salt-dependent hypertension. Here, the functional response to D3 receptor activation was investigated in spontaneously hypertensive rats (SHR) and their normotensive Wistar-Kyoto rats (WKY). In addition, expression of the D3 receptor gene was studied in both rat strains. In clearance experiments, Ringer solution was infused at baseline in thiopental-anesthetized SHR and WKY (each n = 8), followed by an infusion of R(+)-7-hydroxy-dipropylaminotetralin (DPAT), a specific D3 receptor agonist. DPAT was infused in two consecutive doses of 0.01 and 0.1 microg/min per kg body weight. During the entire experiment mean arterial blood pressure was significantly higher (1.5-fold) in adult SHR when compared to age-matched WKY. In both groups DPAT infusion induced a similar dose-dependent increase in urinary flow rate and sodium excretion by a maximum of 2.3-fold and 3.5-fold, respectively. DPAT also increased the glomerular filtration rate in both SHR and WKY. Reverse transcription-polymerase chain reaction studies of whole kidney samples showed no significant differences between young prehypertensive and adult hypertensive SHR when compared to age-matched normotensive WKY. In summary, pharmacological dopamine D3 receptor activation induces a uniform renal response in SHR and WKY. Together with the similar D3 receptor gene expression in both rat strains, which is independent of age or blood pressure levels, the results do not support the notion that the dopamine D3 receptor system is involved in the pathogenesis of hypertension in the SHR model.
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Affiliation(s)
- Gerd Luippold
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Tübingen, Tübingen, Germany.
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Luippold G, Max A, Albinus M, Osswald H, Mühlbauer B. Role of the renin-angiotensin system in the compensation of quinpirole-induced blood pressure decrease. Naunyn Schmiedebergs Arch Pharmacol 2003; 367:427-33. [PMID: 12709781 DOI: 10.1007/s00210-003-0740-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2002] [Accepted: 02/18/2003] [Indexed: 11/24/2022]
Abstract
The dopamine D(2)-like receptor agonist quinpirole has been reported to lower blood pressure. This effect appears to be mediated via activation of presynaptic D(2)-like receptors inhibiting the stimulated neural norepinephrine release. The aim of the present study was to investigate the role of renal nerves and the renin-angiotensin system (RAS) in the blood pressure lowering effect of quinpirole. Therefore, clearance experiments using different doses of quinpirole (0.3 to 100 microg/kg/min) were performed in thiopental-anesthetized rats with intact kidneys (INN) or 5 to 7 days after bilateral renal denervation (DNX). The functional involvement of the RAS in the blood pressure lowering effect of quinpirole was determined in rats pretreated with a subpressor dose of angiotensin II (10 microg/kg/min) or in rats pretreated with the angiotensin II (AT(1)) receptor antagonist losartan, in a subdepressor dose (10 microg/kg/min). Quinpirole dose-dependently decreased mean arterial blood pressure (MAP) by up to 29%. This blood pressure lowering effect of quinpirole was observed at lower doses in DNX rats when compared with INN animals (ED(50): 0.98 microg/kg/min in DNX vs. 6.02 microg/kg/min in INN animals). Quinpirole in a dose of 3 microg/kg/min, which did not affect MAP in vehicle treated INN rats, significantly reduced MAP in rats with losartan pretreatment. In DNX rats pretreated with angiotensin II the MAP-response to the infusion of 3 microg/kg/min quinpirole was clearly attenuated in comparison with untreated DNX animals. Our data show that stimulation of dopamine D(2)-like receptors dose-dependently decreased blood pressure, which was potentiated by both interruption of the renal innervation and AT(1) receptor blockade, while exogenous ANG II restored the enhancement of the blood pressure response to quinpirole. We conclude that the increased vasodilatory effect of quinpirole after renal denervation might depend on a decreased activity of the RAS.
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Affiliation(s)
- Gerd Luippold
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Tübingen, Wilhelmstrasse 56, 72074 Tübingen, Germany.
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Abstract
Renal function was studied in mice of different ages. In metabolic cage experiments, the renal electrolyte excretion was similar in young (n = 8; 5- to 7-wk-old) and adult (n = 6; 20- to 22-wk-old) CD-1 (ICR) BR mice, whereas spontaneous drinking volume and urinary flow rate were significantly higher in the adult compared with the young mice. Subsequently, the renal functional reserve was investigated by amino acid (AA) infusion (10%) in anesthetized young (n = 8) and adult (n = 6) mice. Because the body weight of adult mice was significantly higher than that of young animals, one group of adult mice (n = 8) received 12.5% AA to ensure that the dose of AA related to body weight was similar in both groups. Young animals constantly infused with Ringer solution served as time controls (n = 8). Glomerular filtration rate (GFR) at baseline was similar in each group. Because of AA, GFR significantly increased in young mice but not in both groups of adult animals, whereas in time controls GFR remained constant. Urinary flow rate and sodium excretion were elevated by AA in young and adult mice. We conclude that in CD-1 mice the first signs of age-related changes in kidney function concern alterations in renal hemodynamics, whereas renal tubular function appears to be preserved.
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Affiliation(s)
- Gerd Luippold
- Department of Pharmacology, Faculty of Medicine, University of Tübingen, D-72074 Tübingen, Germany.
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Kloor D, Delabar U, Mühlbauer B, Luippold G, Osswald H. Tissue levels of S-adenosylhomocysteine in the rat kidney: effects of ischemia and homocysteine. Biochem Pharmacol 2002; 63:809-15. [PMID: 11992651 DOI: 10.1016/s0006-2952(01)00892-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Most S-adenosylmethionine (AdoMet)-dependent methyltransferases are regulated in vivo by the AdoMet/S-adenosylhomocysteine (AdoHcy) ratio, also termed as "methylation potential." Since adenosine inhibits in vitro AdoHcy hydrolysis and since adenosine tissue levels increase during hypoxia, it can be predicted that AdoHcy levels may increase in the rat kidney in parallel of those of adenosine. Therefore, the present investigation was performed to assess changes of renal AdoHcy and AdoMet tissue contents during ischemia and after administration of adenosine and homocysteine or both in the ischemic rat kidney. In anesthetized rats ischemia of the kidney was induced by renal artery occlusion for various time intervals. Adenosine and homocysteine were infused into the renal artery of the ischemic kidney. To induce a hyperhomocysteinemia homocysteine was continuously infused. The kidneys were removed and immediately snap-frozen. Tissue contents of AdoHcy, AdoMet, adenosine and adenine nucleotides were analyzed by means of HPLC. Under normoxic condition the tissue contents of AdoHcy, AdoMet and adenosine were 0.7+/-0.05, 44.1+/-1.0 and 3.8+/-0.1nmol/g wet weight, respectively. Renal ischemia for 30min resulted in an increase of AdoHcy levels from 0.7+/-0.05 to 9.1+/-0.6nmol/g wet weight and in a dramatic decrease of the AdoMet/AdoHcy ratio and energy charge from 65.1+/-5.6 to 2.8+/-0.2 and from 0.87+/-0.01 to 0.25+/-0.01, respectively. Application of exogenous adenosine into the ischemic kidney did not result in further AdoHcy accumulation. However, when homocysteine was infused into the ischemic kidney, AdoHcy increased five-fold above control levels, during 5min ischemia. Systemic infusion of homocysteine leads to a reduction of the methylation potential also in the normoxic kidney. We conclude that (i) the methylation potential in the kidney is markedly reduced during ischemia, mainly due to accumulation of AdoHcy; (ii) elevation of AdoHcy tissue content during ischemia is the result of the inhibition of AdoHcy hydrolysis; (iii) homocysteine is rate limiting for AdoHcy synthesis in the ischemic kidney; (iv) under normoxic conditions hyperhomocysteinemia can affect the methylation potential in the renal tissue.
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Affiliation(s)
- Doris Kloor
- Department of Pharmacology, Faculty of Medicine, University of Tübingen, Wilhelmstrasse 56, D-72074, Tübingen, Germany.
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27
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Abstract
Alterations in the dopaminergic system may contribute to the pathogenesis of hypertension. Dopamine D(3) receptors have been shown to be involved in the regulation of sodium balance and hemodynamics in rodents. For determining the role of D(3) receptors in salt-dependent hypertension, clearance experiments were performed in anesthetized salt-sensitive (DS) and salt-resistant (DR) Dahl rats that were fed a standard diet with either normal (0.2%) or high (4%) sodium content for 21 to 26 d, which induced hypertension in DS but not in DR rats. The D(3) receptor agonist R(+)-7-hydroxydipropyl-aminotetralin (7-OH-DPAT) increased GFR by up to 35% and urinary sodium excretion by up to 4.4-fold in DR rats that were on both normal and high-sodium diet. 7-OH-DPAT-induced natriuresis also was observed in DS rats that were on normal diet but not in hypertensive DS rats that were on high-salt diet. No GFR response to 7-OH-DPAT was found in DS rats, irrespective of sodium diet. The diminished functional response to D(3) receptor stimulation in DS rats was associated with a significantly lower [(3)H]-7-OH-DPAT binding to renal membrane protein when comparing DS with DR rats. Consequently, DR rats were treated with BSF 135170, a novel, highly selective D(3) receptor antagonist, for 29 d. Whereas no change in systolic BP was observed during normal diet, high sodium intake significantly increased BP by almost 40 mmHg. In summary, both expression and function of the renal dopamine D(3) receptor are impaired in salt-sensitive Dahl rats. Together with the induction of salt-dependent hypertension in genetically salt-resistant Dahl rats by D(3) receptor blockade, the data strongly suggest that the deficiency in dopamine D(3) receptors represents an important pathophysiological factor in the development of salt-dependent hypertension.
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Affiliation(s)
- Gerd Luippold
- Department of Pharmacology, University of Tübingen, Tübingen, Germany
| | | | - Matthias Mai
- Department of Pharmacology, University of Tübingen, Tübingen, Germany
| | - Doris Kloor
- Department of Pharmacology, University of Tübingen, Tübingen, Germany
| | | | - Gerhard Gross
- Department of Pharmacology, Knoll AG, Ludwigshafen, Germany
| | - Bernd Mühlbauer
- Department of Pharmacology, University of Tübingen, Tübingen, Germany
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Luippold G, Schneider S, Marto M, Benöhr P, Mühlbauer B. Pharmacokinetics of two oral prednisolone tablet formulations in healthy volunteers. Arzneimittelforschung 2001; 51:911-5. [PMID: 11765593 DOI: 10.1055/s-0031-1300136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Two prednisolone (CAS 50-24-8) formulations (Prednisolone 50 mg Ferring tablets as the test preparation and tablets of a reference preparation) were investigated in 13 healthy volunteers in order to prove bioequivalence between these preparations. A single oral dose of 50 mg was given using a randomized, two-way cross-over design with a wash-out period of one week. Blood samples for determination of prednisolone plasma concentrations were collected up to 15 h following drug administration. Additionally, in vitro tests were performed with tablets from the same lots to determine dissolution characteristics. Prednisolone concentrations were measured by means of validated HPLC with UV-detection. Maximum concentrations (Cmax) of 1020.9 +/- 57.8 and 1053.3 +/- 55.7 ng/ml were achieved for the test and the reference preparation, respectively. The AUC0-infinity was 212.2 +/- 13.2 micrograms.min/ml (test preparation) and 222.2 +/- 14.3 micrograms.min/ml (reference preparation). The 90% confidence intervals of the test to reference ratios were within the range of 80-125% with 97.8-101.3% for Cmax and 98.1-100.4% for AUC0-infinity. The time to reach maximum plasma concentration (tmax) tended to be lower (-25%) in the test (39.6 +/- 6.4 min) as compared to the reference preparation (52.8 +/- 9.0 min). Interestingly, this difference correlated well with the observation of a more rapid dissolution rate of the test preparation by some 10 min. Both prednisolone formulations were well tolerated. Based on the results obtained in this study, (1) bioequivalence between the test and the reference preparation was clearly demonstrated and (2) a positive correlation between dissolution rate observed in vitro and tmax as measured in vivo was found.
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Affiliation(s)
- G Luippold
- Department of Pharmacology, Medical Faculty, University of Tübingen, Tübingen, Germany.
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29
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Abstract
The relative bioavailability of different prednisolone (CAS 50-24-8) tablet formulations (Prednisolon Ferring 2, 5, and 20 mg) was investigated in comparison to a reference formulation. The study was performed in a GCP/ICH-conform manner using a randomized cross-over design in 13 healthy volunteers. With respect to the pharmacokinetic parameters Cmax (maximal prednisolone concentration), AUC0-12 h (area under the concentration-time curve until 12 h after drug intake), AUC0-infinity (area under the concentration-time curve until infinity), and t1/2 (elimination half-life time), 10 x 2 mg prednisolone tablets did not show any relevant differences as compared to the reference (1 x 20 mg) meaning that the 90% confidence intervals were within the given 0.80-1.25 limits for the decision of bioequivalence. Although not statistically significant, tmax (time to reach the maximal prednisolone plasma concentration) was 11 min shorter regarding the test preparation as compared to the reference. The pharmacokinetic parameters of 4 x 5 prednisolone tablets were also well in accordance with the reference. The most important parameters Cmax, AUC and t1/2 were within the defined limits for the acceptance of bioequivalence and, in addition, tmax did not show any significant differences. The 20 mg prednisolone tablet formulation showed almost identical parameters of Cmax, AUC, t1/2 und tmax in comparison to the reference substance. Taken together, the results of the bioavailability parameters indicate the bioequivalence of the three prednisolone test preparations as compared to the reference.
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Affiliation(s)
- G Luippold
- Department of Pharmacology, University of Tübingen, Germany.
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30
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Luippold G, Beilharz M, Mühlbauer B. Reduction of glomerular hyperfiltration by dopamine D(2)-like receptor blockade in experimental diabetes mellitus. Nephrol Dial Transplant 2001; 16:1350-6. [PMID: 11427624 DOI: 10.1093/ndt/16.7.1350] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Dopamine D(2)-like receptors are involved in the physiological response of renal haemodynamics to amino-acid infusion. The present study was performed to investigate whether domperidone, a D(2)-like receptor antagonist, modulates the pathological hyperfiltration in experimental diabetes mellitus. METHODS Renal function was studied in anaesthetized rats 2 weeks after induction of moderate diabetes mellitus by streptozotocin, and in non-diabetic controls. Rats in both groups continuously received domperidone or vehicle via drinking water. Following infusion of Ringer's saline for measurement of baseline values, an i.v. amino-acid load was applied to investigate the renal functional reserve. RESULTS In vehicle-treated diabetic rats baseline glomerular filtration rate and renal plasma flow were significantly higher compared with controls (1.10+/- 0.04 vs. 0.83+/-0.02 (P<0.004) and 4.83+/-0.26 vs 3.32+/-0.24 ml/min/100 g body weight (bw) (P<0.001) respectively). Domperidone completely normalized glomerular filtration rate and renal plasma flow in diabetic rats to values observed in vehicle-treated controls (0.81+/-0.07 (P=0.740) and 3.35+/- 0.30 ml/min/100 g bw (P=0.889) respectively). In the clearance experiments, arterial blood pressure, urinary flow rate and sodium excretion did not significantly differ when comparing the four groups. However, in conscious rats, urinary flow rate and sodium excretion were significantly higher in diabetic rats compared with non-diabetic controls. In both non-diabetic groups, amino-acid infusion induced a significant glomerular hyperfiltration that was completely absent in diabetic rats, and restored by domperidone treatment. In conscious vehicle-treated diabetic rats urinary albumin excretion was enhanced (449.0+/-47.7 vs. 185.7+/- 18.1 microg/24 h in non-diabetic rats (P<0.001)) and significantly lowered in diabetic rats by domperidone treatment (109.8+/-15.4 microg/24 h (P<0.001)). CONCLUSION The data suggest that dopaminergic mechanisms are involved in the changes in renal haemodynamics during early experimental diabetes mellitus in rats.
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Affiliation(s)
- G Luippold
- Department of Pharmacology, University of Tübingen, Tübingen, Germany
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Abstract
AIMS In rodents, blockade of dopamine D2-like receptors abolishes both the physiological increase in glomerular filtration rate (GFR) induced by amino acids and the pathological hyperfiltration in experimental diabetes mellitus. This study addressed the contribution of dopamine D2-like receptors to changes in renal haemodynamics after amino acid infusion in humans. METHODS Twelve healthy volunteers participated in this double-blind, randomized, cross-over study. GFR and renal blood flow (RPF) were assessed by renal clearance of inulin and p-aminohippuric acid (PAH), respectively. Following infusion of 0.45% saline at baseline, an electrolyte-balanced solution of mixed amino acids (10%) was infused. Prior to the experiments, the subjects received orally either placebo, or sulpiride (10 mg kg-1), a centrally and peripherally acting D2-like receptor antagonist, or domperidone (1 mg kg-1) which affects only peripheral D2-like receptors. RESULTS In the placebo series, amino acid infusion significantly increased GFR and RPF by up to 15.8 +/- 5.3% and 14.4 +/- 6.1%, respectively, while mean blood pressure and heart rate remained unchanged. Pretreatment with domperidone only marginally altered the renal response to amino acids (maximal increase by 13.2 +/- 5.6 and 11.9 +/- 4.0% in GFR and RPF, respectively), while sulpiride completely abolished the renal haemodynamic changes induced by amino acids. Total and fractional urinary sodium excretion as well as urinary osmolality were similar at baseline and increased in response to amino acids, to the same extent, in all series. No changes in renal dopamine excretion occurred. CONCLUSION The results indicate that in man dopamine D2-like receptors are involved in the renal haemodynamic response to amino acid infusion. Whether dopamine D2-like receptor blockade diminishes glomerular hyperfiltration in pathological states requires clinical investigations.
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Affiliation(s)
- G Luippold
- Department of Pharmacology, University of Tübingen, Centre of Clinical Pharmacology Tübingen-Stuttgart, D-72074 Tübingen, Germany.
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Luippold G, Benöhr P, Piesch C, Heyne N, Mühlbauer B. Urinary dopamine excretion in healthy volunteers: effect of sodium diet and acute water load. Pflugers Arch 2000; 440:28-33. [PMID: 10863994 DOI: 10.1007/s004240000280] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present study was designed to investigate, in human subjects, urinary dopamine excretion under different conditions of sodium and water homeostasis. In a cross-over trial, ten healthy volunteers were subjected to low-salt (LS; dietary salt restriction, sodium chloride (NaCl) intake <5 g per day), normal-salt (NS; normal food ad libitum), and high-salt (HS; normal food plus NaCl 100 mg/kg per day) regimens for 8 days in a randomized order. On day 7, urine was collected for 24 h. The variations in urinary sodium excretion reflected the dietary salt intake (LS: 16.3+/-4.7; NS: 144.1+/-18.2; HS: 221.9+/-12.9 mmol 24 h(-1) 1.73 m(-2)), but were not accompanied by significant changes in urinary dopamine excretion. On day 8, clearance studies showed that an acute oral water load of 1500 ml did not alter glomerular filtration rate or renal plasma flow but significantly increased urinary flow rate without affecting dopamine excretion. Assuming that excreted dopamine is not metabolized or reabsorbed during the tubular passage, both the unchanged urinary dopamine output in spite of 14-fold variations in sodium excretion and its independence of an acute water load argue against the hypothesis that dopamine in the tubular lumen acts as a natriuretic and/or diuretic factor in humans.
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Affiliation(s)
- G Luippold
- Department of Pharmacology, University of Tübingen, Germany.
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Luippold G, Schneider S, Vallon V, Osswald H, Mühlbauer B. Postglomerular vasoconstriction induced by dopamine D(3) receptor activation in anesthetized rats. Am J Physiol Renal Physiol 2000; 278:F570-5. [PMID: 10751217 DOI: 10.1152/ajprenal.2000.278.4.f570] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the present study we investigated the renal hemodynamic effects of dopamine D(3) receptor activation by R(+)-7-hydroxy-dipropylaminotetraline (7-OH-DPAT) in thiopental-anesthetized Sprague-Dawley rats. In clearance experiments infusion of 7-OH-DPAT (0.01-1.0 microg. kg(-1). min(-1)) dose-dependently elevated glomerular filtration rate (GFR) without affecting mean arterial blood pressure (MAP). In renal blood flow experiments 7-OH-DPAT infusion (1.0 microg. kg(-1). min(-1)) increased GFR by 16 +/- 2%, associated with an unexpected fall in renal blood flow by 20 +/- 3% and a significant elevation of renal vascular resistance by 18 +/- 3%. The renal hemodynamic changes were not influenced by pretreatment with the D(2)-receptor antagonist S(-)-sulpiride but were completely abolished during D(3) receptor inhibition by 5,6-dimethoxy-2-(di-n-propylamino)indane (U-99194A). In micropuncture experiments 7-OH-DPAT (1.0 microg. kg(-1). min(-1)) significantly elevated stop-flow pressure measured in the early proximal tubules and reduced hydrostatic pressure at the first branching point of the efferent arteriole without altering MAP. We conclude from these data that pharmacological activation of dopamine D(3) receptors affects renal hemodynamics in anesthetized rats by preferential postglomerular vasoconstriction.
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Affiliation(s)
- G Luippold
- Department of Pharmacology, University of Tübingen, D-72074 Tübingen, Germany.
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34
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Abstract
It is well accepted that dopamine receptors play an important role in the regulation of cardiovascular and kidney function. Most of the knowledge on the renal actions of dopamine has been accumulated focussing on the prototypes of the two known dopamine receptor subfamilies, i.e. D1 and D2. The dopamine D3 receptor is a member of the D2-like subfamily and has been intensively studied in the neurosciences. Recently, the peripheral actions of this receptor subtype have also raised considerable interest as well because its effects on kidney function appear to be different from that of the other dopamine receptors. This short overview will summarize the data reported and add new results on the role of D3 receptors in the regulation of renal function as well as their potential pathophysiological implications.
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Affiliation(s)
- B Mühlbauer
- Department of Pharmacology, University of Tübingen, Germany
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35
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Luippold G, Benöhr P, Piesch C, Heyne N, Mühlbauer B. Urinary dopamine excretion in healthy volunteers: effect of sodium diet and acute water load. Pflugers Arch 2000. [DOI: 10.1007/s004240051018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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36
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Luippold G, Küster E, Vallon V, Osswald H, Mühlbauer B. Dopamine D3 receptors in the rat kidney: glomerular and tubular actions. Nephrol Dial Transplant 1999; 14 Suppl 4:24-5. [PMID: 10463201 DOI: 10.1093/ndt/14.suppl_4.24] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- G Luippold
- Department of Pharmacology, University of Tübingen, Germany
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37
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Luippold G, Delabar U, Kloor D, Mühlbauer B. Erratum to ‘‘Simultaneous determination of adenosine, S-adenosylhomocysteine and S-adenosylmethionine in biological samples using solid-phase extraction and high-performance liquid chromatography. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s0378-4347(99)00182-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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38
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Delabar U, Kloor D, Luippold G, Mühlbauer B. Simultaneous determination of adenosine, S-adenosylhomocysteine and S-adenosylmethionine in biological samples using solid-phase extraction and high-performance liquid chromatography. J Chromatogr B Biomed Sci Appl 1999; 724:231-8. [PMID: 10219663 DOI: 10.1016/s0378-4347(98)00580-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A sensitive and rapid method for measuring simultaneously adenosine, S-adenosylhomocysteine and S-adenosylmethionine in renal tissue, and for the analysis of adenosine and S-adenosylhomocysteine concentrations in the urine is presented. Separation and quantification of the nucleosides are performed following solid-phase extraction by reversed-phase ion-pair high-performance liquid chromatography with a binary gradient system. N6-Methyladenosine is used as the internal standard. This method is characterized by an absolute recovery of over 90% of the nucleosides plus the following limits of quantification: 0.25-1.0 nmol/g wet weight for renal tissue and 0.25-0.5 microM for urine. The relative recovery (corrected for internal standard) of the three nucleosides ranges between 98.1 +/- 2.6% and 102.5 +/- 4.0% for renal tissue and urine, respectively (mean +/- S.D., n = 3). Since the adenosine content in kidney tissue increases instantly after the onset of ischemia, a stop freezing technique is mandatory to observe the tissue levels of the nucleosides under normoxic conditions. The resulting tissue contents of adenosine, S-adenosylhomocysteine and S-adenosylmethionine in normoxic rat kidney are 5.64 +/- 2.2, 0.67 +/- 0.18 and 46.2 +/- 1.9 nmol/g wet weight, respectively (mean +/- S.D., n = 6). Urine concentrations of adenosine and S-adenosylhomocysteine of man and rat are in the low microM range and are negatively correlated with urine flow-rate.
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Affiliation(s)
- U Delabar
- Department of Pharmacology, Medical Faculty, University of Tübingen, Germany
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Luippold G, Küster E, Joos TO, Mühlbauer B. Dopamine D3 receptor activation modulates renal function in anesthetized rats. Naunyn Schmiedebergs Arch Pharmacol 1998; 358:690-3. [PMID: 9879731 DOI: 10.1007/pl00005314] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The renal effects of the D3 receptor agonist R(+)-7-hydroxy-dipropyl-aminotetraline (7-OH-DPAT) were studied in anesthetized Sprague-Dawley rats using standard clearance experiments. 7-OH-DPAT infusion (0.01, 0.1, and 1.0 microg kg(-1) min(-1)) dose-dependently increased glomerular filtration rate (GFR) compared to baseline by a maximum of 20+/-2% while arterial blood pressure was not affected. Heart rate was not altered during the two lower doses of 7-OH-DPAT whereas a slight reduction occurred due to infusion of 1.0 microg kg(-1) min(-1). In contrast, higher doses of 7-OH-DPAT, starting from 3 microg kg(-1) min(-1), markedly influenced systemic hemodynamics. In addition to the hyperfiltration, 7-OH-DPAT (1.0 microg kg(-1) min(-1)) also induced a significant diuresis (27.7+/-4.3 microl min(-1) 100 g(-1) vs 16.2+/-5.4 microl min(-1) 100 g(-1)) and increased both absolute (3.30+/-0.58 micromol min(-1) 100 g(-1) vs 0.95+/-0.26 micromol min(-1) 100 g(-1)) and fractional sodium excretion (2.48+/-0.32% vs 0.79+/-0.19%). These changes in renal function were not modulated by pretreatment with the D2 receptor antagonist S(-)-sulpiride but abolished by the D3 antagonist 5,6-dimethoxy-2-(di-n-propylamino)indane (U-99194A). In coincidence with the action of 7-OH-DPAT on both glomerular and tubular function, reverse transcription-polymerase chain reaction (RT-PCR) revealed the expression of D3 receptors in both glomerular and tubular fractions of kidneys taken from Sprague-Dawley rats. These data indicate that D3 receptors in the kidney are involved in the regulation of renal hemodynamics and tubular function.
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Affiliation(s)
- G Luippold
- Department of Pharmacology, University of Tübingen, Germany
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40
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Luippold G, Osswald H, Mühlbauer B. Renal effects of exogenous dopamine: modulation by renal nerves and dopamine receptor antagonists. Naunyn Schmiedebergs Arch Pharmacol 1998; 358:445-51. [PMID: 9826067 DOI: 10.1007/pl00005277] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The modulation of the renal response to exogenous dopamine by renal denervation (DNX) and dopamine receptor antagonists was investigated in thiopental-anesthetized Sprague-Dawley rats. Experiments were performed after reaching stable systemic hemodynamics and urinary flow rate. These conditions were obtained with an infusion rate of approximately 1.2% of body weight per hour. In the vehicle group (VHC) i.v. infusion of dopamine (1, 3 and 9 microg kg(-1) min(-1) significantly increased glomerular filtration rate (GFR), assessed by renal clearance of [3H]inulin, by 14+/-1.5, 16+/-1.6 and 31+/-2.6%, respectively. Infusion of 1 and 3 microg kg(-1) min(-1) dopamine did not change systemic hemodynamics while the highest dose elevated heart rate, potentially contributing to the GFR increase. The specific D1 receptor antagonist SCH 23390 (10 microg kg(-l) min(-1) i.v.) did not affect the GFR response to dopamine infusion. In contrast, domperidone (DOM; 8 microg kg(-1) min(-1) i.v.), a specific, peripherally acting D2 antagonist, attenuated the glomerular hyperfiltration induced by the three doses of dopamine to 11+/-1.7, 13+/-2.2 and 16+/-2.6%, respectively. DNX diminished the GFR response to dopamine infusion to almost the same extent (11+/-2.8, 10+/-2.2 and 17+/-2.6%, respectively) as did DOM. When DNX animals were treated with DOM, the GFR responses to dopamine were further attenuated to non-significant increases. These additive effects of DOM and DNX suggest that two different mechanisms are involved. Both DNX and SCH 23390 decreased sodium excretion at baseline whereas DOM enhanced it. Under the present experimental condition, neither D1 nor D2 receptor blockade affected the natriuretic and diuretic response to dopamine. Whereas D1 receptors do not appear to be involved, both D2 receptors and renal nerves play a role in the renal hemodynamic response to dopamine, indicating involvement of both pre- and postsynaptical dopamine receptors.
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Affiliation(s)
- G Luippold
- Department of Pharmacology, University of Tübingen, Germany
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41
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Luippold G, Mühlbauer B. Dopamine D2 receptors mediate glomerular hyperfiltration due to amino acids. J Pharmacol Exp Ther 1998; 286:1248-52. [PMID: 9732385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Renal dopamine has been proposed to be involved in the regulation of glomerular filtration rate (GFR). Because inhibition of dopamine D2 receptors abolishes the renal hyperfiltration due to amino acid load, we tested the hypothesis that pharmacological activation of D2-like receptors mimicked this renal response. In anesthetized rats, quinpirole (0.3 microgram . 100 g-1 . min-1), an agonist for receptors of the D2-like family, caused an increase in GFR by 20 +/- 2%, which corresponded to that provoked by infusion of an 10% amino acid solution. The D2 receptor antagonist S(-)-sulpiride that acts both centrally and peripherally completely abolished the renal hemodynamic response to quinpirole and to amino acids whereas domperidone, a peripherally acting D2 receptor antagonist, inhibited this hyperfiltration only in part. Urinary dopamine excretion increased in response to amino acid infusion whether GFR increased or not. We conclude that, in anesthetized rats, dopamine D2 receptors contribute to the amino acid-induced hyperfiltration and that both central and peripheral receptors might be involved, whereas dopamine excreted into the urine does not appear to play a functional role in this renal hemodynamic response.
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Affiliation(s)
- G Luippold
- Department of Pharmacology, University of Tübingen, Germany
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42
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Mühlbauer B, Luippold G, Vallon V, Spitzenberger F, Russ H, Osswald H, Schömig E. Disprocynium24 induces a dopamine-independent, eukaliuric diuresis and natriuresis in the anaesthetized rat. Naunyn Schmiedebergs Arch Pharmacol 1997; 356:846-9. [PMID: 9453472 DOI: 10.1007/pl00005126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the anaesthetized rat, intravenous administration of the isocyanine 1,1'-diisopropyl-2,4'-cyanine (disprocynium24) at doses up to 600 microg/kg resulted in marked diuresis and natriuresis without affecting urinary potassium excretion. Fractional sodium excretion was increased over 10-fold indicating a high ceiling-diuretic action. The effects of disprocynium24 on renal function were accompanied by a dose-dependent reduction in heart rate (HR) and mean arterial blood pressure (MAP). Acute administration of 600 microg/kg disprocynium24 decreased MAP by 25% and, in addition, caused a fall in glomerular filtration rate (GFR). Since i) disprocynium24 has been shown to interfere with urinary dopamine excretion (UDAV) and ii) dopamine has been implicated with the regulation of renal sodium excretion, we hypothesized that the effects of disprocynium24 might be mediated by its effects on renal dopamine handling. The following findings, however, argue against this hypothesis. First, administration of disprocynium24 in single doses up to 600 microg/kg caused a diuresis and natriuresis, but did not significantly affect U(DA)V. Second, neither the systemic nor the renal response to disprocynium24 were markedly altered by pretreatment with the dopamine D1- or D2-receptor blockers SCH23390 (10 microg x kg(-1) x min[-1]) or S(-)sulpiride (15 microg x kg(-1) x min[-1]), respectively.
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Affiliation(s)
- B Mühlbauer
- Pharmakologisches Institut der Universität Tübingen, Germany
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Mühlbauer B, Gleiter CH, Gies C, Luippold G, Löschmann PA. Renal response to infusion of dopamine precursors in anaesthetized rats. Naunyn Schmiedebergs Arch Pharmacol 1997; 356:838-45. [PMID: 9453471 DOI: 10.1007/pl00005125] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the present study the renal response to intravenous infusion of the catecholamine precursors L-dihydroxyphenylalanine (L-DOPA) or L-tyrosine was investigated in thiopentone sodium-anaesthetized Sprague-Dawley rats. Glomerular filtration rate (GFR) was assessed by renal clearance of inulin, urinary concentration of dopamine (U(DA)V) by HPLC and sodium excretion (U(Na)V) by flame photometry. We found that basal U(DA)V was 6.5 +/- 0.5 pmol/min per 100 g body weight (mean +/- SEM). Intravenous infusion of L-tyrosine at 0. 1-3.0 micromol/min dose dependently enhanced U(DA)V (17 +/- 3 to 144 +/- 14 pmol/min respectively) with higher doses of L-tyrosine resulting in no further increase in U(DA)V. Compared with L-tyrosine administration significantly lower doses of L-DOPA (0.07 to 35 nmol/min) caused increases in U(DA)V which were orders of magnitude higher (18 +/- 1 to 7800 +/- 470 pmol/min, respectively) and did not show saturation characteristics. GFR did not change in response to L-tyrosine or L-DOPA infusion. No variations in urinary flow rate or in U(Na)V could be observed which were significantly correlated to changes in U(DA)V. In contrast, intravenous infusion of dopamine at a dose of 6 nmol/min significantly increased GFR by 35 +/- 6.2% and urinary flow rate by over 2-fold. Immunohistochemistry with light microscopy revealed no tyrosine hydroxylase in the kidney. Therefore, dopamine synthesis in the tubular cells mainly depends on the renal supply of L-DOPA. The unchanged GFR and U(Na)V in spite of large variations of U(DA)V argue against the hypothesis that intratubular dopamine plays a functional role in the regulation of hemodynamics or sodium transport in the kidney. Renal dopamine excretion may rather represent an effective pathway for the elimination of catecholamine precursors from the plasma.
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Affiliation(s)
- B Mühlbauer
- Pharmakologisches Institut der Universität Tübingen, Germany
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Abstract
In proteins released from quiescent human neutrophils during incubation, 21% of the methionine (Met) residues were found to be oxidized. However, the portion of oxidized Met in extracellular proteins increased to 66% after stimulating the cells with zymosan and to 75% after stimulation with phorbol myristate acetate (PMA). Generation of such high levels of oxidized Met in native proteins by activated neutrophils has, so far, not been observed. The presence of superoxide dismutase during incubation of PMA-stimulated cells produced a negligible effect on methionine oxidation, while the presence of catalase resulted in a methionine sulfoxide (Met(O)) content of only 28% in the released proteins. It is proposed that the conversion of Met to Met(O) in these proteins predominantly occurs by action of the myeloperoxidase/H2O2/Cl- system in the extracellular space.
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Affiliation(s)
- I Beck-Speier
- Projekt Inhalation der Gesellschaft für Strahlen- und Umweltforschung München, Arbeitsgruppe Biochemie, Neuherberg, FRG
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Lebsanft J, Luippold G, Schwarz LR. Uptake of taurocholate by isolated gamma-glutamyltranspeptidase positive, putatively preneoplastic hepatocytes from 2-acetylaminofluorene treated rats. Carcinogenesis 1986; 7:1925-6. [PMID: 2876787 DOI: 10.1093/carcin/7.11.1925] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Uptake of the bile acid taurocholate was determined in liver cells isolated from male Wistar rats fed a standard diet or a diet containing 2-acetylaminofluorene (2-AAF). In addition, uptake was analysed in unaltered, gamma-glutamyltranspeptidase (gamma-GTase) negative, and in putatively preneoplastic, gamma-GTase positive, hepatocytes separated from the total liver cell preparation isolated from the 2-AAF-treated animals. Total hepatocytes from the carcinogen-treated rats showed a approximately 50% decrease in the maximum rate of taurocholate transport compared to cells from untreated animals. Bile acid uptake in gamma-GTase positive and negative liver cells revealed that Vmax was decreased by 44 +/- 14% in the preneoplastic cell population. Since the Km value did not differ significantly it appears that the number of carrier molecules is reduced in the early preneoplastic hepatocytes. Our results show a partial loss of a liver-specific function in early preneoplastic gamma-GTase positive hepatocytes.
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Forster U, Luippold G, Schwarz LR. Induction of monooxygenase and UDP-glucuronosyltransferase activities in primary cultures of rat hepatocytes. Drug Metab Dispos 1986; 14:353-60. [PMID: 2872038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The inducibility of two monooxygenase and UDP-glucuronosyltransferase (GT) forms was studied in primary cultures of adult rat hepatocytes. The following enzyme activities were determined: cytochrome P-448-dependent ethoxyresorufin O-deethylase (ERDE) and cytochrome P-450-dependent aldrin epoxidase (AE), and, furthermore, the GT form(s) metabolizing 3-hydroxybenzo(a)pyrene (GT1) and the GT form(s) metabolizing 4-hydroxybiphenyl (GT2). The results were as follows. The activity of AE and GT2 decreased markedly during the first days of culture, whereas ERDE and GT1 remained stable or even increased slightly. The maintenance of ERDE activity was dependent on the presence of dexamethasone. Pregnenolone-16 alpha-carbonitrile (PCN), phenobarbital (PB), and benz(a)anthracene (BA) induced the activity of ERDE in hepatocytes cultured in HM 84 medium by a factor of 4, 8, and 12, respectively. Similar factors of induction were obtained at the fifth day of culture using a modified Leibovitz L-15 medium. However, the time course of induction differed greatly in the two media. BA and PB had an additive effect on ERDE activity, suggesting different mechanisms of action for the two inducers. Monoclonal antibodies directed against cytochrome P-448 inhibited ERDE activities induced by BA and PB to a similar extent. Neither PB nor PCN significantly increased AE activity. However, these compounds induced GT2. BA did not affect GT2 but induced GT1. The present results show that the culture of adult rat hepatocytes changes the relative distribution of monooxygenase and GT forms. The response to inducers resembles only partially that observed in vivo.
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Lebsanft J, Luippold G, Schwarz LR. Activities of drug-metabolizing enzymes in isolated gamma-glutamyltranspeptidase positive preneoplastic hepatocytes from carcinogen treated rats. Cancer Lett 1985; 29:29-36. [PMID: 2866028 DOI: 10.1016/0304-3835(85)90119-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Drug metabolizing enzyme activities were determined in isolated putatively preneoplastic, gamma-glutamyltranspeptidase (gamma-GT) positive hepatocytes from male Wistar rats fed 2-acetylaminofluorene (AAF). The cells were isolated by affinity binding to anti-gamma-GT antibody coated dishes, the resulting suspension contained 60-87% gamma-GT-positive cells. Cytochrome P-450 dependent metabolism of benzo[a]pyrene, aldrin and ethoxyresorufin was 43-54% lower than in the parent cell suspension, glucuronidation of 3-hydroxybenzo[a]pyrene (3-OH-BP) and hydrolysis of styrene oxide were increased 1.5- and 1.4-fold, respectively. The altered pattern of drug metabolizing enzyme activities in isolated gamma-GT-positive hepatocytes is consistent with the increase in resistance of preneoplastic liver cells to hepatotoxins.
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