Stimulation of growth hormone by kisspeptin antagonists in ewes

Smith, J. T., Roseweir, A. , Millar, M., Clarke, I. and Millar, R. P. (2018) Stimulation of growth hormone by kisspeptin antagonists in ewes. Journal of Endocrinology, 237(2), pp. 165-173. (doi: 10.1530/JOE-18-0074) (PMID:29549187)

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Abstract

Kisspeptin signalling is indispensable for fertility, stimulating gonadotropin- releasing hormone (GnRH) secretion and mediating gonadal steroid feedback on GnRH neurons. Moreover, kisspeptin neurons have been implicated in other non-reproductive neuroendocrine roles. Kisspeptin appears to also regulate growth hormone secretion but much of the data appear contradictory. We sought to clarify a potential role of kisspeptin in GH regulation by examining the effect of kisspeptin antagonists on growth hormone (GH) secretion in ewes under various physiological conditions. Our data show clear and robust increases in GH secretion following lateral ventricle or third ventricle infusion of kisspeptin antagonists p-234 and p-271 in either ovariectomised or anestrous ewes. Central infusion of kisspeptin-10 had no effect on GH secretion. To determine the level at which kisspeptin may influence GH secretion we examined expression of the cognate kisspeptin receptor, GPR54, in pituitary cells and showed by immunocytochemistry that the majority of somatotropes express GPR54 while expression was largely negative in other pituitary cells. Overall, we have demonstrated that blocking kisspeptin signalling by antagonists stimulates GH secretion in ewes and that this is likely mediated by inhibiting endogenous kisspeptin activation of GPR54 expressed on somatotropes. The findings suggest that endogenous kisspeptin inhibits growth hormone secretion through GPR54 expressed on somatotropes.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Roseweir, Dr Antonia
Authors: Smith, J. T., Roseweir, A., Millar, M., Clarke, I., and Millar, R. P.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cancer Sciences
College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
Journal Name:Journal of Endocrinology
Publisher:BioScientifica Ltd.
ISSN:0022-0795
ISSN (Online):1479-6805
Published Online:16 March 2018
Copyright Holders:Copyright © 2018 Society for Endocrinology
First Published:First published in Journal of Endocrinology 237(2): 165-173
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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