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Tashiro J, Sugiura A, Warita T, Irie N, Dwi Cahyadi D, Ishikawa T, Warita K. CYP11A1 silencing suppresses HMGCR expression via cholesterol accumulation and sensitizes CRPC cell line DU-145 to atorvastatin. J Pharmacol Sci 2023; 153:104-112. [PMID: 37770151 DOI: 10.1016/j.jphs.2023.08.002] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 08/07/2023] [Accepted: 08/17/2023] [Indexed: 10/03/2023] Open
Abstract
Statins, which are cholesterol synthesis inhibitors, are well-known therapeutics for dyslipidemia; however, some studies have anticipated their use as anticancer agents. However, epithelial cancer cells show strong resistance to statins through an increased expression of HMG-CoA reductase (HMGCR), an inhibitory target of statins. Castration-resistant prostate cancer (CRPC) cells synthesize androgens from cholesterol on their own. We performed suppression of CYP11A1, a rate-limiting enzyme in androgen synthesis from cholesterol, using siRNA or inhibitors, to examine the effect of steroidogenesis inhibition on statin sensitivity in CRPC cells. Here, we suggested that CYP11A1 silencing sensitized the statin-resistant CRPC cell line DU-145 to atorvastatin via HMGCR downregulation by an increase in intracellular free cholesterol. We further demonstrated that CYP11A1 silencing induced epithelial-mesenchymal transition, which converted DU-145 cells into a statin-sensitive phenotype. This suggests that concomitant use of CYP11A1 inhibitors could be an effective approach for overcoming statin resistance in CRPC. Moreover, we showed that ketoconazole, a CYP11A1 inhibitor, sensitized DU-145 cells to atorvastatin, although not all the molecular events observed in CYP11A1 silencing were reproducible. Although further studies are necessary to clarify the detailed mechanisms, ketoconazole may be effective as a concomitant drug that potentiates the anticancer effect of atorvastatin.
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Affiliation(s)
- Jiro Tashiro
- Department of Veterinary Anatomy, Joint Graduate School of Veterinary Sciences, Tottori University, Tottori, Japan
| | - Akihiro Sugiura
- Department of Veterinary Anatomy, Joint Graduate School of Veterinary Sciences, Tottori University, Tottori, Japan
| | - Tomoko Warita
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, Hyogo, Japan
| | - Nanami Irie
- Graduate School of Science and Technology, Kwansei Gakuin University, Hyogo, Japan
| | - Danang Dwi Cahyadi
- Department of Veterinary Anatomy, Joint Graduate School of Veterinary Sciences, Tottori University, Tottori, Japan
| | - Takuro Ishikawa
- Department of Anatomy, School of Medicine, Aichi Medical University, Aichi, Japan; Joint Department of Veterinary Medicine, Tottori University, Tottori, Japan.
| | - Katsuhiko Warita
- Department of Veterinary Anatomy, Joint Graduate School of Veterinary Sciences, Tottori University, Tottori, Japan; Joint Department of Veterinary Medicine, Tottori University, Tottori, Japan.
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Walter I, Adam S, Gentilini MV, Kany AM, Brengel C, Thomann A, Sparwasser T, Köhnke J, Hartmann RW. Structure-Activity Relationship and Mode-Of-Action Studies Highlight 1-(4-Biphenylylmethyl)-1H-imidazole-Derived Small Molecules as Potent CYP121 Inhibitors. ChemMedChem 2021; 16:2786-2801. [PMID: 34010508 PMCID: PMC8519103 DOI: 10.1002/cmdc.202100283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Indexed: 11/29/2022]
Abstract
CYP121 of Mycobacterium tuberculosis (Mtb) is an essential target for the development of novel potent drugs against tuberculosis (TB). Besides known antifungal azoles, further compounds of the azole class were recently identified as CYP121 inhibitors with antimycobacterial activity. Herein, we report the screening of a similarity-oriented library based on the former hit compound, the evaluation of affinity toward CYP121, and activity against M. bovis BCG. The results enabled a comprehensive SAR study, which was extended through the synthesis of promising compounds and led to the identification of favorable features for affinity and/or activity and hit compounds with 2.7-fold improved potency. Mode of action studies show that the hit compounds inhibit substrate conversion and highlighted CYP121 as the main antimycobacterial target of our compounds. Exemplified complex crystal structures of CYP121 with three inhibitors reveal a common binding site. Engaging in both hydrophobic interactions as well as hydrogen bonding to the sixth iron ligand, our compounds block a solvent channel leading to the active site heme. Additionally, we report the first CYP inhibitors that are able to reduce the intracellular replication of M. bovis BCG in macrophages, emphasizing their potential as future drug candidates against TB.
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Affiliation(s)
- Isabell Walter
- Department for Drug Design and OptimizationHelmholtz Institute for Pharmaceutical Research SaarlandCampus E8.166123SaarbrückenGermany
| | - Sebastian Adam
- Workgroup Structural Biology of Biosynthetic EnzymesHelmholtz Institute for Pharmaceutical Research Saarland (HIPS)Helmholtz Centre for Infection Research (HZI)Saarland UniversitySaarbrückenGermany
| | - Maria Virginia Gentilini
- Institute of Infection Immunology, TWINCORECentre for Experimental and Clinical Infection ResearchA Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI)HannoverGermany
| | - Andreas M. Kany
- Department for Drug Design and OptimizationHelmholtz Institute for Pharmaceutical Research SaarlandCampus E8.166123SaarbrückenGermany
| | - Christian Brengel
- Department for Drug Design and OptimizationHelmholtz Institute for Pharmaceutical Research SaarlandCampus E8.166123SaarbrückenGermany
| | - Andreas Thomann
- Department for Drug Design and OptimizationHelmholtz Institute for Pharmaceutical Research SaarlandCampus E8.166123SaarbrückenGermany
| | - Tim Sparwasser
- Institute of Infection Immunology, TWINCORECentre for Experimental and Clinical Infection ResearchA Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI)HannoverGermany
| | - Jesko Köhnke
- Workgroup Structural Biology of Biosynthetic EnzymesHelmholtz Institute for Pharmaceutical Research Saarland (HIPS)Helmholtz Centre for Infection Research (HZI)Saarland UniversitySaarbrückenGermany
| | - Rolf W. Hartmann
- Department for Drug Design and OptimizationHelmholtz Institute for Pharmaceutical Research SaarlandCampus E8.166123SaarbrückenGermany
- Department of PharmacyPharmaceutical and Medicinal ChemistrySaarland UniversityCampus C2.366123SaarbrückenGermany
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Wang Y, Yuan K, Li X, Su Z, Li X, Guan H, Su Y, Ge HS, Ge RS. Leukemia inhibitory factor stimulates steroidogenesis of rat immature Leydig cells via increasing the expression of steroidogenic acute regulatory protein. Growth Factors 2016; 34:166-176. [PMID: 27760485 DOI: 10.1080/08977194.2016.1183199] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Leukemia inhibitory factor (LIF) has many physiological roles. However, its effects on Leydig cell development are still unclear. Rat immature and adult Leydig cells were cultured with different concentrations of LIF alone or in combination with luteinizing hormone (LH) for 24 h. LIF (1 and 10 ng/ml) significantly increased androgen production in immature Leydig cells, but had no effects on testosterone production in adult Leydig cells. Further studies revealed that LIF dose-dependently increased Star and Hsd17b3 expression levels in immature Leydig cells. Gene microarray revealed that the upregulation of anti-oxidative genes and Star might contribute to LIF-induced androgen production. In conclusion, LIF has stimulatory effects on androgen production in rat immature Leydig cells.
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Affiliation(s)
- Yiyan Wang
- a Department of Anesthesiology , The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , Zhejiang , People's Republic of China and
| | - Kaiming Yuan
- a Department of Anesthesiology , The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , Zhejiang , People's Republic of China and
| | - Xiaoheng Li
- a Department of Anesthesiology , The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , Zhejiang , People's Republic of China and
| | - Zhijian Su
- b Department of Cell Biology , College of Life Science and Technology, Jinan University , Guangzhou , People's Republic of China
| | - Xingwang Li
- a Department of Anesthesiology , The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , Zhejiang , People's Republic of China and
| | - Hongguo Guan
- a Department of Anesthesiology , The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , Zhejiang , People's Republic of China and
| | - Ying Su
- a Department of Anesthesiology , The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , Zhejiang , People's Republic of China and
| | - Hong-Shan Ge
- a Department of Anesthesiology , The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , Zhejiang , People's Republic of China and
| | - Ren-Shan Ge
- a Department of Anesthesiology , The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , Zhejiang , People's Republic of China and
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Chortis V, Taylor AE, Schneider P, Tomlinson JW, Hughes BA, O'Neil DM, Libé R, Allolio B, Bertagna X, Bertherat J, Beuschlein F, Fassnacht M, Karavitaki N, Mannelli M, Mantero F, Opocher G, Porfiri E, Quinkler M, Sherlock M, Terzolo M, Nightingale P, Shackleton CHL, Stewart PM, Hahner S, Arlt W. Mitotane therapy in adrenocortical cancer induces CYP3A4 and inhibits 5α-reductase, explaining the need for personalized glucocorticoid and androgen replacement. J Clin Endocrinol Metab 2013; 98:161-71. [PMID: 23162091 DOI: 10.1210/jc.2012-2851] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Mitotane [1-(2-chlorophenyl)-1-(4-chlorophenyl)-2,2-dichloroethane] is the first-line treatment for metastatic adrenocortical carcinoma (ACC) and is also regularly used in the adjuvant setting after presumed complete removal of the primary tumor. Mitotane is considered an adrenolytic substance, but there is limited information on distinct effects on steroidogenesis. However, adrenal insufficiency and male hypogonadism are widely recognized side effects of mitotane treatment. OBJECTIVE Our objective was to define the impact of mitotane treatment on in vivo steroidogenesis in patients with ACC. SETTING AND DESIGN At seven European specialist referral centers for adrenal tumors, we analyzed 24-h urine samples (n = 127) collected from patients with ACC before and during mitotane therapy in the adjuvant setting (n = 23) or for metastatic ACC (n = 104). Urinary steroid metabolite excretion was profiled by gas chromatography/mass spectrometry in comparison with healthy controls (n = 88). RESULTS We found a sharp increase in the excretion of 6β-hydroxycortisol over cortisol (P < 0.001), indicative of a strong induction of the major drug-metabolizing enzyme cytochrome P450 3A4. The contribution of 6β-hydroxycortisol to total glucocorticoid metabolites increased from 2% (median, interquartile range 1-4%) to 56% (39-71%) during mitotane treatment. Furthermore, we documented strong inhibition of systemic 5α-reductase activity, indicated by a significant decrease in 5α-reduced steroids, including 5α-tetrahydrocortisol, 5α-tetrahydrocorticosterone, and androsterone (all P < 0.001). The degree of inhibition was similar to that in patients with inactivating 5α-reductase type 2 mutations (n = 23) and patients receiving finasteride (n = 5), but cluster analysis of steroid data revealed a pattern of inhibition distinct from these two groups. Longitudinal data showed rapid onset and long-lasting duration of the observed effects. CONCLUSIONS Cytochrome P450 3A4 induction by mitotane results in rapid inactivation of more than 50% of administered hydrocortisone, explaining the need for doubling hydrocortisone replacement in mitotane-treated patients. Strong inhibition of 5α-reductase activity is in line with the clinical observation of relative inefficiency of testosterone replacement in mitotane-treated men, calling for replacement by 5α-reduced androgens.
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Affiliation(s)
- Vasileios Chortis
- Centre for Endocrinology, Diabetes and Metabolism, School of Clinical & Experimental Medicine, University of Birmingham, Birmingham, B15 2TT, United Kingdom
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Zsippai A, Szabó DR, Tömböl Z, Szabó PM, Éder K, Pállinger É, Gaillard RC, Patócs A, Tóth S, Falus A, Rácz K, Igaz P. Effects of mitotane on gene expression in the adrenocortical cell line NCI-H295R: a microarray study. Pharmacogenomics 2012; 13:1351-61. [DOI: 10.2217/pgs.12.116] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: The adrenolytic agent mitotane is widely used in the treatment of adrenocortical cancer; however, its mechanism of action is poorly elucidated. We have studied mitotane-induced mRNA expression changes in the NCI-H295R adrenocortical cancer cell line. Materials & methods: Cell viability and hormone assays were used to select the optimal mitotane concentration effectively inhibiting hormone secretion without affecting cell viability. RNA isolated from cultures treated for 48 and 72 h was subjected to Agilent 4×44K microarray platforms. Microarray results were validated by quantitative reverse-transcription PCR. Results: Altogether, 117 significantly differentially expressed genes were detected at 48 h and 72 h (p < 0.05) in mitotane-treated samples relative to controls. Three significantly underexpressed genes involved in steroid hormone biosynthesis (HSD3B1, HSD3B2 and CYP21A2) and four significantly overexpressed genes (GDF15, ALDH1L2, TRIB3 and SERPINE2) have been validated. Conclusion: Gene-expression changes might be involved in the adrenal action of mitotane and in the inhibition of hormone secretion. Original submitted 20 January 2012; Revision submitted 17 May 2012
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Affiliation(s)
- Adrienn Zsippai
- 2nd Department of Medicine, Faculty of Medicine, Semmelweis University, Szentkirályi street 46, H-1088 Budapest, Hungary
| | - Diana Rita Szabó
- 2nd Department of Medicine, Faculty of Medicine, Semmelweis University, Szentkirályi street 46, H-1088 Budapest, Hungary
| | - Zsófia Tömböl
- 2nd Department of Medicine, Faculty of Medicine, Semmelweis University, Szentkirályi street 46, H-1088 Budapest, Hungary
| | - Peter M Szabó
- 2nd Department of Medicine, Faculty of Medicine, Semmelweis University, Szentkirályi street 46, H-1088 Budapest, Hungary
| | - Katalin Éder
- Department of Genetics, Cell & Immunobiology, Faculty of Medicine, Semmelweis University, Nagyvárad square 4, H-1089 Budapest, Hungary
| | - Éva Pállinger
- Department of Genetics, Cell & Immunobiology, Faculty of Medicine, Semmelweis University, Nagyvárad square 4, H-1089 Budapest, Hungary
| | - Rolf C Gaillard
- Division of Endocrinology, Diabetology & Metabolism, University Hospital Lausanne, Rue du Bugnon 46., CH-1011 Lausanne, Switzerland
| | - Attila Patócs
- Molecular Medicine Research Group, Hungarian Academy of Sciences & Semmelweis University, Szentkirályi street 46, H-1088 Budapest, Hungary
| | - Sára Tóth
- Department of Genetics, Cell & Immunobiology, Faculty of Medicine, Semmelweis University, Nagyvárad square 4, H-1089 Budapest, Hungary
| | - András Falus
- Department of Genetics, Cell & Immunobiology, Faculty of Medicine, Semmelweis University, Nagyvárad square 4, H-1089 Budapest, Hungary
| | - Károly Rácz
- 2nd Department of Medicine, Faculty of Medicine, Semmelweis University, Szentkirályi street 46, H-1088 Budapest, Hungary
| | - Peter Igaz
- 2nd Department of Medicine, Faculty of Medicine, Semmelweis University, Szentkirályi street 46, H-1088 Budapest, Hungary
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Gyllenhammar I, Eriksson H, Söderqvist A, Lindberg RH, Fick J, Berg C. Clotrimazole exposure modulates aromatase activity in gonads and brain during gonadal differentiation in Xenopus tropicalis frogs. Aquat Toxicol 2009; 91:102-109. [PMID: 19036460 DOI: 10.1016/j.aquatox.2008.10.005] [Citation(s) in RCA: 18] [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] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 09/24/2008] [Accepted: 10/06/2008] [Indexed: 05/27/2023]
Abstract
Clotrimazole is a pharmaceutical used for treatment of fungal infections. It has been found in surface waters outside municipal wastewater treatment plants but data are scarce regarding its effects on aquatic organisms. It is known that clotrimazole and other imidazole fungicides are inhibitors of the enzyme aromatase (CYP 19). Aromatase converts androgens into estrogens and is suggested to be involved in the sex differentiation in amphibians. The aim of the present study was to evaluate effects of larval exposure to clotrimazole on aromatase activity in brain and gonads, and on gonadal differentiation in Xenopus tropicalis frogs. Another purpose was to determine if larval exposure to ethynylestradiol (EE(2)), at a concentration known to cause male-to-female sex reversal, affects aromatase activity in brain and gonads during gonadal differentiation. Tadpoles were exposed from shortly after hatching (Nieuwkoop and Faber developmental stages 47-48) until complete metamorphosis (NF stage 66) to 6, 41, and 375 nM clotrimazole or 100 nM (nominal) EE(2). Aromatase activity was measured in the brain and gonad/kidney complex of tadpoles during gonadal differentiation (NF stage 56) and, in the clotrimazole experiment, also at metamorphosis. In clotrimazole-exposed tadpoles gonadal aromatase activity increased over exposure time in the 41 and 375 nM groups but did not differ significantly from the control group. Gonadal aromatase activity was increased in both sexes exposed to 41 and 375 nM clotrimazole at metamorphosis. Brain aromatase activity was decreased in tadpoles (NF stage 56) exposed to 375 nM clotrimazole, but at metamorphosis no differences were seen between groups or between sexes. No effects of clotrimazole on sex ratio or gonadal histology were noted at completed metamorphosis. EE(2)-exposed tadpoles had a slightly decreased gonadal aromatase activity, though not significantly different from control group, and there was no effect of EE(2) on brain aromatase activity. All EE(2)-exposed tadpoles developed ovaries. These findings indicate that estrogen-induced ovarian differentiation is not paralleled by increased gonadal aromatase activity in X. tropicalis. Further studies are needed, especially on developmental reproductive toxicity, to assess the risk for endocrine disruption in wild amphibians posed by clotrimazole and other imidazole fungicides.
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Affiliation(s)
- Irina Gyllenhammar
- Department of Environmental Toxicology, Uppsala University, Centre for Reproductive Biology in Uppsala (CRU), Norbyvägen 18 A, 75236 Uppsala, Sweden.
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Casley WL, Ogrodowczyk C, Larocque L, Jaentschke B, LeBlanc-Westwood C, Menzies JA, Whitehouse L, Hefford MA, Aubin RA, Thorn CF, Whitehead AS, Li X. Cytotoxic doses of ketoconazole affect expression of a subset of hepatic genes. J Toxicol Environ Health A 2007; 70:1946-1955. [PMID: 17966066 DOI: 10.1080/15287390701551407] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Ketoconazole is a widely prescribed antifungal drug, which has also been investigated as an anticancer therapy in both clinical and pre-clinical settings. However, severe hepatic injuries were reported to be associated with the use of ketoconazole, even in patients routinely monitored for their liver functions. Several questions concerning ketoconazole-induced hepatic injury remain unanswered, including (1) does ketoconazole alter cytochrome P450 expression at the transcriptional level?, (2) what types of gene products responsible for cytotoxicity are induced by ketoconazole?, and (3) what role do the major metabolites of ketoconazole play in this pathophysiologic process? A mouse model was employed to investigate hepatic gene expression following hepatotoxic doses of ketoconazole. Hepatic gene expression was analyzed using a toxicogenomic microarray platform, which is comprised of cDNA probes generated from livers exposed to various hepatoxicants. These hepatoxicants fall into five well-studied toxicological categories: peroxisome proliferators, aryl hydrocarbon receptor agonists, noncoplanar polychlorinated biphenyls, inflammatory agents, and hypoxia-inducing agents. Nine genes encoding enzymes involved in Phase I metabolism and one Phase II enzyme (glutathione S-transferase) were found to be upregulated. Serum amyloid A (SAA1/2) and hepcidin were the only genes that were downregulated among the 2364 genes assessed. In vitro cytotoxicity and transcription analyses revealed that SAA and hepcidin are associated with the general toxicity of ketoconazole, and might be usefully explored as generalized surrogate markers of xenobiotic-induced hepatic injury. Finally, it was shown that the primary metabolite of ketoconazole (de-N-acetyl ketoconazole) is largely responsible for the hepatoxicity and the downregulation of SAA and hepcidin.
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Affiliation(s)
- William L Casley
- Center for Biologics Research, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
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Rodriguez RJ, Buckholz CJ. Hepatotoxicity of ketoconazole in Sprague-Dawley rats: glutathione depletion, flavin-containing monooxygenases-mediated bioactivation and hepatic covalent binding. Xenobiotica 2003; 33:429-41. [PMID: 12745877 DOI: 10.1080/0049825031000072243] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
1. This study has examined ketoconazole (KT)-induced hepatotoxicity in vivo and in vitro, using male Sprague-Dawley rats with [(3)H]KT (1.5 micro Ci mg(-1)) at 40 and 90 mg KT kg(-1) doses. Blood and liver samples were collected from 0 to 24 h for alanine aminotransaminase (ALT), glutathione (GSH) and covalent binding analyses. 2. Covalent binding occurred as early as 0.5 h, peaked at 2 h (0.026 +/- 0.01 nmol KT mg(-1) protein) and 8 h (0.088 +/- 0.04 nmol KT mg(-1) protein) for 40 and 90 mg KT kg(-1) doses, respectively. ALT levels increased at 0.5 h for the 40 and 90 mg KT kg(-1) doses (44.3 and 56.4 U ml(-1), respectively) relative to control, 22.7 U ml(-1). At 24 h, the 90 mg KT kg(-1) dose reduced hepatic GSH levels from 9.92 +/- 1.1 to 4.76 +/- 0.3 nmol GSH mg(-1) protein. 3. The role of the flavin-containing monooxygenases (FMO) utilized Sprague-Dawley microsomes with 1, 10 and 100 micro M [(3)H]KT. Maximum covalent binding occurring at 100 micro M KT. Heat inactivation of microsomal FMO significantly decreased covalent binding by 75%, whereas 1 mM GSH significantly reduced covalent binding by 65%. 4. Thus, KT-induced hepatotoxicity is dose- and time-dependent and appears to be FMO mediated, in part, to metabolites that may react with protein and, possibly, GSH.
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Affiliation(s)
- R J Rodriguez
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331-3507, USA.
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Abstract
The effects of anticonvulsants on the activities of cytochromes P-450(17alpha,lyase) (CYP17), P-450arom (CYP19), P-450C21 (CYP21), P-450SCC (CYP11A1), and P-450(11beta) (CYP11B1) mono-oxygenase systems were studied using rat testicular microsomes, human placental microsomes, bovine adrenocortical microsomes, bovine adrenocortical mitochondria and purified cytochrome P-450(11beta). Phenytoin, clonazepam and carbamazepine inhibited the steroidogenesis catalysed by these cytochrome P-450 mono-oxygenase systems and the Ki values for each anticonvulsant were determined. Neither hydantoin nor sodium valproate inhibited the activities of steroidogenic cytochromes P-450. When the activities of cytochromes P-450arom and P-450C21 were measured in the presence of anticonvulsants, the Ki values (0.15 mM) for phenytoin were close to the plasma concentration of phenytoin under therapeutic conditions. Phenytoin, clonazepam and carbamazepine directly inhibited the monooxygenase activities of cytochromes P-450, because they did not affect the activities of NADPH-cytochrome P-450 reductase, NADPH-adrenoferredoxin reductase and adrenoferredoxin.
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Affiliation(s)
- T Ohnishi
- Department of Biochemistry, Kagawa Medical School, Kita-gun, Japan
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Schraag S, Pawlik M, Mohl U, Böhm BO, Georgieff M. The role of ascorbic acid and xylitol in etomidate-induced adrenocortical suppression in humans: . Eur J Anaesthesiol 1996; 13:346-51. [DOI: 10.1097/00003643-199607000-00007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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