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Roelfsema F, Yang R, Veldhuis JD. Interleukin-2 Transiently Inhibits Pulsatile Growth Hormone Secretion in Young but not Older Healthy Men. J Clin Endocrinol Metab 2021; 106:2855-2864. [PMID: 34212195 PMCID: PMC8475215 DOI: 10.1210/clinem/dgab484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Interleukin-2 (IL-2), a proinflammatory cytokine, has been used to treat malignancies. Increased cortisol and adrenocorticotropin (ACTH) were noted, but growth hormone (GH) secretion was not investigated in detail. OBJECTIVE We quantified GH secretion after a single subcutaneous injection of IL-2 in 17 young and 18 older healthy men in relation to dose, age, and body composition. METHODS This was a placebo-controlled, blinded, prospectively randomized, crossover study. At 20:00 hours IL-2 (3 or 6 million units/m2) or saline was injected subcutaneously. Lights were off between 23:00 and 07:00 hours. Blood was sampled at 10-minute intervals for 24 hours. Outcome measures included convolution analysis of GH secretion. RESULTS GH profiles were pulsatile under both experimental conditions and lower in older than young volunteers. Since the effect of IL-2 might be time limited, GH analyses were performed on the complete 24-hour series and the 6 hours after IL-2 administration. Total and pulsatile 24-hour GH secretion decreased nonsignificantly. Pulsatile secretion fell over the first 6 hours after IL-2 (P = .03), with visceral fat as a covariate (P = .003), but not age (P = .10). Plots of cumulative 2-hour bins of GH pulse mass showed a distinction by treatment and age groups: A temporary GH decrease of 32% and 28% occurred in the first 2-hour bins after midnight (P = .02 and .04) in young participants, whereas in older individuals no differences were present at any time point. CONCLUSION This study demonstrates that IL-2 temporarily diminishes GH secretion in young, but not older, men.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Internal Medicine, Section Endocrinology, Leiden University Medical, Center, 2333ZA Leiden, the Netherlands
| | - Rebecca Yang
- Endocrine Research Unit, Mayo Clinic College of Medicine, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905,USA
| | - Johannes D Veldhuis
- Endocrine Research Unit, Mayo Clinic College of Medicine, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905,USA
- Correspondence: Johannes D. Veldhuis, MD, Endocrine Research Unit, Mayo Clinic College of Medicine, Center for Translational Science Activities, Mayo Clinic, Rochester, MN 55905, USA.
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Cheng Y, Chen T, Song J, Teng Z, Wang C, Wang S, Lu G, Feng T, Qi Q, Xi Q, Liu S, Hao L, Zhang Y. Pituitary miRNAs target GHRHR splice variants to regulate GH synthesis by mediating different intracellular signalling pathways. RNA Biol 2020; 17:1754-1766. [PMID: 32508238 DOI: 10.1080/15476286.2020.1778295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Growth hormone (GH), whose synthesis and release are mainly regulated by intracellular signals mediated by growth hormone-releasing hormone receptor (GHRHR), is one of the major pituitary hormones and critical regulators of organism growth, metabolism, and immunoregulation. Pig GHRHR splice variants (SVs) may activate different signalling pathways via the variable C-terminal by alternative splicing, and SVs have the potential to change microRNA (miRNA) binding sites. In this study, we first confirmed the existence of pig GHRHR SVs (i.e., GHRHR, GHRHR SV1 and SV2) and demonstrated the inhibitory effects of critical pituitary miRNAs (i.e., let-7e and miR-328-5p) on GH synthesis and cell proliferation of primary pituitary cells. The SVs of GHRHR targeted by let-7e and miR-328-5p were predicted via bioinformatics analysis and verified by performing dual-luciferase reporter assays and detecting the expression of target transcripts. The differential responses of let-7e, and miR-328-5p to GH-releasing hormone and the changes in signalling pathways mediated by GHRHR suggested that let-7e and miR-328-5p were involved in GH synthesis mediated by GHRHR SVs, indicating that the two miRNAs played different roles by different ways. Finally, results showed that the protein coded by the GHRHR transcript regulated GH through the NO/NOS signalling pathway, whereas that coded by SV1 and SV2 regulated GH through the PKA/CREB signalling pathway, which was confirmed by the changes in signalling pathways after transfecting the expression vectors of GHRHR SVs to GH3 cells. To the best of our knowledge, this paper is the first to report pituitary miRNAs regulate GH synthesis by targeting the different SVs of GHRHR.
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Affiliation(s)
- Yunyun Cheng
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China.,Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University , Guangzhou, China
| | - Ting Chen
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University , Guangzhou, China
| | - Jie Song
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Zhaohui Teng
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China.,Research and Development Centre, Dalian Mogue Biotech Co., Ltd , Dalian, China
| | - Chunli Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Siyao Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Guanhong Lu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Tianqi Feng
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Qien Qi
- School of Life Science and Engineering, Foshan University , Foshan China
| | - Qianyun Xi
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University , Guangzhou, China
| | - Songcai Liu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Linlin Hao
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Yongliang Zhang
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University , Guangzhou, China
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Mao J, Qiu B, Mei F, Liu F, Feng Z, Fan J, Nie J, Huang L, Liao X, Wang Z, Zeng J, Weng Z, Zang N, Qi S, Bao Y. Interleukin-1α leads to growth hormone deficiency in adamantinomatous craniopharyngioma by targeting pericytes: implication in pituitary fibrosis. Metabolism 2019; 101:153998. [PMID: 31666193 DOI: 10.1016/j.metabol.2019.153998] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/18/2019] [Accepted: 09/20/2019] [Indexed: 02/03/2023]
Abstract
BACKGROUND The incidence of growth hormone deficiency (GHD) in adamantinomatous craniopharyngioma (aCP) is significantly higher than in other sellar region tumors, but the possible mechanism is still elusive. A high level of inflammatory responses is another feature of aCP. We investigated the internal connection between interleukin-1α (IL-1α) and GHD, while focusing on its biological activities in pituitary fibrosis. MATERIALS AND METHODS To diagnosis of GHD, the Body Mass Index (BMI), Insulin Like Growth Factor-1(IGF-1) and peak growth hormone (GH) values after insulin stimulation test of 15 aCP patients were recorded. Histological staining was performed on the aCP samples. Levels of 9 proinflammatory cytokines in tumor tissue and cell supernatant were detected using Millipore bead arrays. The effect of IL-1α on GH secretion was evaluated in vivo and in vitro. Western blot, qRT-PCR and cell functional assays were used to explore the potential mechanism through which IL-1α acts on GH secretion. The stereotactic ALZET osmotic pump technique was used to simulate aCP secretion of proinflammatory cytokines in rats. Recombinant IL-1α (rrIL-1α) and conditioned media (CM) prepared from the supernatant of aCP cells was infused directly into the intra-sellar at a rate of 1 μl/h over 28 days, and then the effects of IL-1α treatment on pathological changes of pituitary gland and GH secretion were measured. To further confirm whether IL-1α affects GH secretion through IL-1R1, an IL-1R1 blocker (IL-1R1a, 10 mg/kg body weight, once daily) was administered subcutaneously from the first day until day 28. RESULTS There was a significant positive correlation between pituitary fibrosis and GHD (rS = 0.756, P = 0.001). A number of cytokines, in particular IL-1α, interleukin-8 (IL-8), and monocyte chemoattractant protein-1 (MCP-1), were elevated in tumor tissue and cell supernatant. Only IL-1α showed a significant difference between the GHD group and the No-GHD group (P < 0.001, F = 6.251 in tumor tissue; P = 0.003, F = 1.529 in cell supernatant). IL-1α significantly reduced GH secretion in coculture of GH3 and pericytes. The activation of pericytes induced by IL-1α was mediated by the IL-1R1 signaling pathway. In vivo, IL-1α induces pituitary fibrosis, further leading to a decreased level of GH. This pathological change was antagonized by IL-1R1a. CONCLUSION This study found that the cross talk between aCP cells and stroma cells in the pituitary, i.e. pericytes, is an essential factor in the formation of GHD, and we propose that neutralization of IL-1α signaling might be a potential therapy for GHD in aCP.
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Affiliation(s)
- Jian Mao
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Binghui Qiu
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Fen Mei
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Fan Liu
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zhanpeng Feng
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Jun Fan
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Jing Nie
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Lijun Huang
- The First School of Clinical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Xixian Liao
- The First School of Clinical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Zhenhao Wang
- The First School of Clinical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Jiahui Zeng
- The First School of Clinical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Zelin Weng
- The First School of Clinical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Nailiang Zang
- The First School of Clinical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Songtao Qi
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
| | - Yun Bao
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
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Vindeløv SD, Hartoft-Nielsen ML, Rasmussen ÅK, Bendtzen K, Kosteljanetz M, Andersson AM, Feldt-Rasmussen U. Interleukin-8 production from human somatotroph adenoma cells is stimulated by interleukin-1β and inhibited by growth hormone releasing hormone and somatostatin. Growth Horm IGF Res 2011; 21:134-139. [PMID: 21658592 DOI: 10.1016/j.ghir.2011.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 03/18/2011] [Accepted: 03/20/2011] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Pituitary adenomas cause morbidity and mortality due to their localization and influence on pituitary hormone secretion. Although the pathogenesis of pituitary adenomas is unclear, studies have indicated that cytokines are involved. We investigated the role of cytokines, in particular interleukin (IL)-8, in the pathogenesis of growth hormone (GH) producing tumours. DESIGN Human somatotroph adenoma tissue was obtained from patients undergoing surgery for acromegaly. The tissue underwent mechanical and enzymatic digestion, was washed, suspended and cultured in 24-chamber plates. After stimulation/inhibition supernatants were harvested. As control of growth hormone producing properties of the cultured cells, GH releasing hormone (GHRH) stimulated and somatostatin inhibited the GH response. RESULTS The cultured adenoma cells released both IL-6 and IL-8 and the secretion was inhibited by GHRH and somatostatin. IL-1β dose-dependently stimulated GH, IL-6 and IL-8 secretion. CONCLUSION Using cultured primary somatotroph adenoma cells as a dynamic method, we found a consistent release not only of IL-6 as described previously, but also of IL-8. This finding could be important for reassessing a role of these cytokines in the pathogenesis of pituitary tumour growth and function, and thus form a basis for targeted therapy. In line with previous studies, our results further indicated a common physiological or pathophysiological reaction of endocrine cells to cytokine stimulation.
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Affiliation(s)
- Signe Diness Vindeløv
- Department of Medical Endocrinology, PE 2132, Rigshospitalet, Copenhagen University Hospital, University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
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Whitlock BK, Daniel JA, Wilborn RR, Elsasser TH, Carroll JA, Sartin JL. Comparative aspects of the endotoxin- and cytokine-induced endocrine cascade influencing neuroendocrine control of growth and reproduction in farm animals. Reprod Domest Anim 2008; 43 Suppl 2:317-23. [PMID: 18638141 DOI: 10.1111/j.1439-0531.2008.01180.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Disease in animals is a well-known inhibitor of growth and reproduction. Earlier studies were initiated to determine the effects of endotoxin on pituitary hormone secretion. These studies found that in sheep, growth hormone (GH) concentration was elevated, whereas insulin-like growth factor-I (IGF-I) was inhibited, as was luteinizing hormone (LH). Examination of the site of action of endotoxin in sheep determined that somatotropes expressed the endotoxin receptor (CD14) and that both endotoxin and interleukin-I beta activated GH secretion directly from the pituitary. In the face of elevated GH, there is a reduction of IGF-I in all species examined. As GH cannot activate IGF-I release during disease, there appears to be a downregulation of GH signalling at the liver, perhaps related to altered nitration of Janus kinase (JAK). In contrast to GH downregulation, LH release is inhibited at the level of the hypothalamus. New insights have been gained in determining the mechanisms by which disease perturbs growth and reproduction, particularly with regard to nitration of critical control pathways, with this perhaps serving as a novel mechanism central to lipopolysaccharide suppression of all signalling pathways. This pathway-based analysis is critical to the developing novel strategies to reverse the detrimental effect of disease on animal production.
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Affiliation(s)
- B K Whitlock
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
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6
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Carroll JA. Bidirectional communication: Growth and immunity in domestic livestock1,2,3,4. J Anim Sci 2008; 86:E126-37. [PMID: 17709773 DOI: 10.2527/jas.2007-0480] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Evidence continues to mount supporting the existence of a bidirectional communication network between the immune system and the somatotropic axis in a variety of species. For more than 4 decades, researchers have sought and identified linkages between the growth axis and the immune system. Although significant advances have been made with regard to elucidation of various bidirectional communication pathways between the immune system and growth axis in humans and rodents, the current paper focuses on the relationships between the immune system and somatotropic axis in sheep, cattle, and swine. Aspects from historical and current research associated with changes in somatotropic function following immune challenges with endotoxin, parasites, viruses, and bacteria have been provided. Collectively, these studies demonstrate that a bidirectional communication network, similar to that described in humans and rodents, also exists in a variety of domestic livestock. Identifying and understanding this bidirectional communication network could have significant economic benefits if it leads to intervention strategies to prevent production losses associated with sickness and disease.
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Affiliation(s)
- J A Carroll
- USDA-ARS-Livestock Issues Research Unit, Lubbock, TX 79409, USA.
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Elsasser TH, Caperna TJ, Li CJ, Kahl S, Sartin JL. Critical control points in the impact of the proinflammatory immune response on growth and metabolism1,2. J Anim Sci 2008; 86:E105-25. [DOI: 10.2527/jas.2007-0634] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Daniel JA, Elsasser TH, Martínez A, Steele B, Whitlock BK, Sartin JL. Interleukin-1beta and tumor necrosis factor-alpha mediation of endotoxin action on growth hormone. Am J Physiol Endocrinol Metab 2005; 289:E650-7. [PMID: 15899940 DOI: 10.1152/ajpendo.00489.2004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In humans and sheep, endotoxin (LPS) administration results in increased growth hormone (GH) concentrations. To determine the role of cytokines in the effect of LPS on GH, sheep were challenged with IL-1beta or TNF-alpha. GH data were compared with results with LH, where the major effects of LPS are known to act via the hypothalamus. Intracerebroventricular (icv) administration of IL-1beta or TNF-alpha did not alter plasma concentrations of GH. Endotoxin was then administered intravenously (iv) in combination with icv injection of IL-1 receptor antagonist (IL-1RA), TNF antagonist (sTNF-R1), or saline. Administration of LPS increased GH (P < 0.0001), although coadministration of IL-1ra or sTNF-R1 icv did not alter GH response to LPS. In contrast, plasma concentrations of LH were profoundly inhibited by icv administration of either cytokine (P < 0.03), but the LH response to LPS was not altered by cytokine antagonists. Intravenous administration of either IL-1beta or TNF-alpha increased plasma concentrations of GH (P < 0.0001). Administration of IL-1RA and sTNF-R1 iv prevented LPS-induced increases in GH. Although LH was suppressed by high iv doses of IL-1beta (P = 0.0063), the antagonists did not alter the LH response to LPS. To determine whether LPS might directly activate GH release, confocal microscopy revealed colocalization of CD14, the LPS receptor, with GH and, to a lesser extent, LH and some prolactin (PRL)-containing cells, but not ACTH or TSH. These data are consistent with the effects of LPS on GH secretion originating through peripheral cytokine presentation to the pituitary, as well as a potential to act directly on selective populations of pituitary cells via CD14.
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Affiliation(s)
- J A Daniel
- Animal and Range Sciences, South Dakota State University, Brookings, South Dakota, USA
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Gong FY, Deng JY, Shi YF. Stimulatory effect of interleukin-1beta on growth hormone gene expression and growth hormone release from rat GH3 cells. Neuroendocrinology 2005; 81:217-28. [PMID: 16043966 DOI: 10.1159/000087160] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Accepted: 02/21/2005] [Indexed: 12/11/2022]
Abstract
Our previous studies demonstrated that interferon gamma increases the human (h) growth hormone (GH) gene promoter activity in rat pituitary GH3 cells, and its regulatory mechanism may be different from the classical GH-releasing hormone-induced regulatory mechanism. Interleukin-1beta (IL-1beta) is thought to induce the release of GH by pituitary cells, but whether or not and by which mechanisms IL-1beta regulates GH synthesis remains unclear. The purpose of our study was thus to investigate the effect of IL-1beta on the hGH gene expression in GH3 rat pituitary tumor cells using stable transfection of the hGH promoter fused to a luciferase reporter gene. Our results showed that IL-1beta (10-10(4) U/ml) increased GH secretion and synthesis and that 10(2) to 10(4) U/ml IL-1beta promoted the luciferase expression in stable GH3 cells, with a maximal action of 1.61 times over that of controls. Among inhibitors of intracellular signaling transduction pathways, mitogen-activated protein kinase kinase (MAPKK/MEK) inhibitor PD98059 (40 microM) and p38 MAPK inhibitor SB203580 (5 microM)blocked completely the stimulatory effect of IL-1beta, and the phosphoinositide 3-kinase inhibitor LY294002 (10 microM) blocked partially the induction of IL-1beta. Western blot analysis demonstrated that IL-1beta increased the activation of phosphorylated MEK and p38 MAPK in GH3 cells. Neither overexpression of Pit-1 nor inhibiting Pit-1 expression affected IL-1beta induction of hGH promoter activity. To identify the DNA sequence that mediated the effect of IL-1beta, six deletion constructs of hGH promoter were created. The stimulatory effect of IL-1beta was abolished following deletion of the -196- to -132-bp fragment. In conclusion, our data show that IL-1beta promotes GH secretion and synthesis by rat pituitary GH3 cells. The stimulatory effect of IL-1beta on the hGH gene promoter appears to require the activation of MEK, p38 MAPK, and phosphoinositide 3-kinase and a fragment of promoter sequence that spans the -196- to -132-bp fragment of the gene, but is unrelated to the Pit-1 protein.
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Affiliation(s)
- Feng-Ying Gong
- Department of Endocrinology, Beijing Union Medical College Hospital, Chinese Academy of Medical Sciences, China
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Katoh K, Shimoguchi R, Ishiwata H, Obara Y. Rapid suppressing action of insulin-like growth factor-I (IGF-I) on GH release from anterior pituitary cells of goats. Domest Anim Endocrinol 2004; 26:177-88. [PMID: 15036373 DOI: 10.1016/j.domaniend.2003.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2003] [Accepted: 10/01/2003] [Indexed: 11/30/2022]
Abstract
Goat anterior pituitary cells were cultured to investigate the effects of insulin-like growth factor-I (IGF-I), insulin, and growth hormone (GH) on basal and GH-releasing hormone (GHRH)-induced GH release. Changes in cellular Ca2+ concentrations were also assessed to enable discussion of the cellular mechanisms of IGF-I. The cells were cultured for 48 h, and then stimulated with GHRH (10 nmol/l) for 30 min, with or without each test substance. In the control cells, IGF-I (10 and 100 ng/ml) significantly raised the basal, but did not change GHRH-induced GH release, resulting in the abolishment of GH release induced by GHRH in the presence of 100 ng/ml IGF-I. However, there was no significant effect of insulin (10, 100, and 1000 microU/ml) on basal and GHRH-induced GH release. In the cells cultured for 48 h with each test substance but stimulated for 30 min without the test substance, no significant change in the basal and GHRH-stimulated GH release was observed. Regardless of treatment, there was no significant effect on intra-cellular GH content. Analysis with a confocal laser microscope revealed that IGF-I (100 ng/ml) significantly increased the basal, but significantly reduced GHRH (10 nmol/l)-induced increase in cellular Ca2+ concentrations. From these findings we conclude that IGF-I exerts an acute suppressing action on the GHRH-induced GH release, which partly involves changes in cellular Ca2+ metabolism in goat somatotrophs.
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Affiliation(s)
- K Katoh
- Department of Animal Physiology, Graduate School of Agriculture, Tohoku University, Tsutsumidori, Aoba-ku, Sendai 981-8555, Japan.
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Daniel JA, Elsasser TH, Morrison CD, Keisler DH, Whitlock BK, Steele B, Pugh D, Sartin JL. Leptin, tumor necrosis factor-α (TNF), and CD14 in ovine adipose tissue and changes in circulating TNF in lean and fat sheep2. J Anim Sci 2003; 81:2590-9. [PMID: 14552388 DOI: 10.2527/2003.81102590x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Four studies were designed to determine whether 1) tumor necrosis factor-alpha (TNF) and the Lipopolysaccharide (LPS) binding ligand, CD14, are produced by sheep adipose tissue; 2) nutritional reserves and/or short-term fasting affect circulating concentrations of TNF; 3) there is a relationship between TNF and metabolic factors in sheep; and 4) inflammation alters circulating concentrations of leptin. In Exp. 1 and 2, ewes were assigned, based on ultrasonic assessments of last-rib subcutaneous fat measurements to fat (fat thickness > 1 cm; mean = 1.52 +/- 0.03 cm) or thin (fat thickness < 1 cm; mean = 0.25 +/- 0.03 cm) groups. Fat and thin ewes were assigned to fed or fasted groups for a total of four groups (fed-fat; fasted-fat; fed-thin; fasted-thin). Fed-ewes had ad libitum access to feed, and fasted-ewes were prohibited feed 48 h before initiation of sample collection. In Exp. 1, subcutaneous fat samples were collected from just above the last rib for detection of TNF and CD14 mRNA, and immunoreactivity. Tumor necrosis factor-alpha-like immunoreactivity in adipocytes was sparse, more pronounced in cells in fed-ewes than fasted-ewes, and localized to membranes between adjacent cells in nucleated regions. Immunoreactivity for CD14 was minimally observed but present in adipocytes and widely expressed in infiltrating monocytes and epithelial vascular cells. Leptin was detected in adipocytes. In Exp. 2, plasma samples collected every 6 h for 24 h were analyzed for plasma concentrations of TNF. Fat ewes had greater plasma concentrations of TNF than thin ewes (P = 0.039). In Exp. 3, wethers were injected i.v. with interleukin-1beta or TNF. Blood samples were collected every 15 min for 8 h following injection. Plasma concentration of leptin was not affected by treatment (P > 0.39). In Exp. 4, wethers were injected with LPS. Blood samples were collected every 15 min for 8 h following injection. Plasma concentration of leptin was not altered by LPS (P > 0.20). These results provide evidence: 1) of TNF-like immunoreactivity within fat tissue; 2) that elements within fatty tissues have CD14 that may allow adipocyte function to be directly affected by LPS; 3) that plasma concentrations of leptin are not altered by LPS treatment; and 4) that circulating concentrations of TNF are elevated with obesity in sheep.
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Affiliation(s)
- J A Daniel
- South Dakota State University, Brookings, SD 57007, USA
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Scacchi M, Pincelli AI, Cavagnini F. Nutritional status in the neuroendocrine control of growth hormone secretion: the model of anorexia nervosa. Front Neuroendocrinol 2003; 24:200-24. [PMID: 14596812 DOI: 10.1016/s0091-3022(03)00014-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Growth hormone (GH) plays a key role not only in the promotion of linear growth but also in the regulation of intermediary metabolism, body composition, and energy expenditure. On the whole, the hormone appears to direct fuel metabolism towards the preferential oxidation of lipids instead of glucose and proteins, and to convey the energy derived from metabolic processes towards the synthesis of proteins. On the other hand, body energy stores and circulating energetic substrates take an important part in the regulation of somatotropin release. Finally, central and peripheral peptides participating in the control of food intake and energy expenditure (neuropeptide Y, leptin, and ghrelin) are also involved in the regulation of GH secretion. Altogether, nutritional status has to be regarded as a major determinant in the regulation of the somatotropin-somatomedin axis in animals and humans. In these latter, overweight is associated with marked impairment of spontaneous and stimulated GH release, while acute dietary restriction and chronic undernutrition induce an amplification of spontaneous secretion together with a clear-cut decrease in insulin-like growth factor I (IGF-I) plasma levels. Thus, over- and undernutrition represent two conditions connoted by GH hypersensitivity and GH resistance, respectively. Anorexia nervosa (AN) is a psychiatric disorder characterized by peculiar changes of the GH-IGF-I axis. In these patients, low circulating IGF-I levels are associated with enhanced GH production rate, highly disordered mode of somatotropin release, and variability of GH responsiveness to different pharmacological challenges. These abnormalities are likely due not only to the lack of negative IGF-I feedback, but also to a primary hypothalamic alteration with increased frequency of growth hormone releasing hormone discharges and decreased somatostatinergic tone. Given the reversal of the above alterations following weight recovery, these abnormalities can be seen as secondary, and possibly adaptive, to nutritional deprivation. The model of AN may provide important insights into the pathophysiology of GH secretion, in particular as regards the mechanisms whereby nutritional status effects its regulation.
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Affiliation(s)
- Massimo Scacchi
- Chair of Endocrinology, University of Milan, Ospedale San Luca IRCCS, Istituto Auxologico Italiano, Milan, Italy
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Mainardi GL, Saleri R, Tamanini C, Baratta M. Effects of interleukin-1-beta, interleukin-6 and tumor necrosis factor-alpha, alone or in association with hexarelin or galanin, on growth hormone gene expression and growth hormone release from pig pituitary cells. Horm Res Paediatr 2003; 58:180-6. [PMID: 12324716 DOI: 10.1159/000065487] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE We studied the effects of IL-1beta, IL-6 and TNF-alpha on GH gene expression and secretion with or without galanin and hexarelin. METHODS Pituitary cells from adult pigs were treated with IL-1beta, IL-6 or TNF-alpha (1, 10 and 100 ng/ml), alone or in association with galanin or hexarelin (10(-8) M): GH mRNA was measured by RT-PCR and GH secretion by ELISA. RESULTS IL-1beta (1, 10 and 100 ng/ml) and IL-6 (1 and 10 ng/ml) significantly (p < 0.05) enhanced GH output. IL-1beta and TNF-alpha (1 and 10 ng/ml) reduced (p < 0.05) the galanin-induced GH secretion and IL-6 (10 ng/ml) potentiated the effect of both GH releasers (p < 0.05). GH gene expression was increased only by IL-6 at the concentrations of 1 and 10 ng/ml, either alone or in association with both galanin and hexarelin. CONCLUSIONS We hypothesize that cytokines may play a paracrine/autocrine role in GH regulation in the pituitary independently from the intracellular pathways of the GH secretagogues.
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Affiliation(s)
- Gian Luca Mainardi
- Department of Animal Production, Veterinary Biotechnology and Food Safety, Section of Veterinary Physiology, University of Parma, Italy
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De A, Churchill L, Obal F, Simasko SM, Krueger JM. GHRH and IL1beta increase cytoplasmic Ca(2+) levels in cultured hypothalamic GABAergic neurons. Brain Res 2002; 949:209-12. [PMID: 12213318 DOI: 10.1016/s0006-8993(02)03157-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
GHRH and IL1beta regulate sleep via the hypothalamus. However, actions of these substances on neurons are poorly understood. In this study, we found both GHRH (100 nM) and IL1beta (1.2 pM) acutely increased cytosolic Ca(2+) in 7.6 and 4.0% of cultured hypothalamic neurons tested, respectively, and 1.2% of neurons responded to both. The neurons that responded were mostly GABAergic (96, 81, and 100% for GHRH, IL1beta, and dual-responsive neurons, respectively).
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Affiliation(s)
- Alok De
- Department of VCAPP, Program in Neuroscience, Washington State University, PO Box 646520, Pullman, WA 99164-6520, USA
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Daniel JA, Whitlock BK, Wagner CG, Sartin JL. Regulation of the growth hormone and luteinizing hormone response to endotoxin in sheep. Domest Anim Endocrinol 2002; 23:361-70. [PMID: 12142252 DOI: 10.1016/s0739-7240(02)00171-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Infectious disease processes cause physiological adaptations in animals to reorder nutrient partitioning and other functions to support host survival. Endocrine, immune and nervous systems largely mediate this process. Using endotoxin injection as a model for catabolic disease processes (such as bacterial septicemia), we have focused our attention on regulation of growth hormone (GH) and luteinizing hormone (LH) secretion in sheep. Endotoxin produces an increase in plasma GH and a decrease in plasma LH concentrations. This pattern can be reproduced, in part, by administration of various cytokines. Antagonists to both interleukin-1 (IL-1) and tumor necrosis factor (TNF) given intravenously (IV) prevented the endotoxin-stimulated increase in GH. Since endotoxin will directly stimulate GH and LH release from cultured pituitary cells, the data suggest a pituitary site of action of the endotoxin to regulate GH. Studies with portal vein cannulated sheep indicated that gonadotropin releasing hormone was inhibited by endotoxin, suggesting a central site of action of endotoxin to regulate LH. However, other studies suggest that endotoxin may also regulate LH secretion at the pituitary. Thus, IL-1 and TNF regulate GH release from the pituitary gland while endotoxin induces a central inhibition of LH release.
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Affiliation(s)
- J A Daniel
- Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University, AL 36849, USA
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Ferrari E, Fioravanti M, Magri F, Solerte SB. Variability of interactions between neuroendocrine and immunological functions in physiological aging and dementia of the Alzheimer's type. Ann N Y Acad Sci 2001; 917:582-96. [PMID: 11268387 DOI: 10.1111/j.1749-6632.2000.tb05424.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A link between neuroendocrine and immunological changes has been suggested in the pathophysiology of dementia of the Alzheimer's type (DAT). Healthy young and old subjects and patients with DAT were recruited to evaluate the chrononeuroendocrine organization of cortisol, GH, and melatonin (MLT) secretions. The study was carried out together with the evaluation of natural killer (NK) cell function: cytotoxic activity (NKCC) and TNF-alpha and IFN-gamma release after exposure to IL-2 (100 U/mL). Moreover, a cerebral morphometric analysis of hippocampus and temporal lobe (MRI) was performed. The activation of hypothalamo-pituitary-adrenal (HPA) axis and the decrease of GH, and MLT nocturnal peaks were associated with normal NKCC and TNF-alpha/IFN-gamma in healthy elderly subjects, whereas in DAT patients the same neuroendocrine changes occurred together with abnormal NKCC (spontaneous and IL-2/IFN-beta-modulated) and with alterations of TNF-alpha/INF-gamma generation from NK. Moreover significant correlations among the increase of NKCC and TNF-alpha and the decrease of cognitive function were found in the DAT group. These correlations were associated with the impairment of nocturnal GH and MLT levels and with the relatively higher serum cortisol concentrations. Moreover, the impairment of cortisol suppression after dexamethasone (1 mg orally at 23:00) was significantly correlated with the increase of spontaneous release of TNF-alpha and with IL-2-modulated NKCC. Finally the imunoneuroendocrine alterations found in DAT were associated with the reduction of cerebral volume in hippocampus and temporal lobes. Taken together these data indicate that the immunoneuroendocrine balance is maintained in physiological aging, whereas NK immune dysregulation in DAT could contribute to altering the neuroendocrine functions and to extend the progression of neurodegeneration and dementia.
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Affiliation(s)
- E Ferrari
- Department of Internal Medicine, Geriatrics and Gerontology Clinic, Post-graduate School of Geriatrics and Endocrinology, University of Pavia, Piazza Borromeo 2, 27100 Pavia, Italy.
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Proinflammatory cytokines (tumor necrosis factor and interleukin 1) stimulate release of high mobility group protein-1 by pituicytes. Surgery 1999. [DOI: 10.1016/s0039-6060(99)70182-0] [Citation(s) in RCA: 219] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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