Stimulation of growth hormone by kisspeptin antagonists in ewes.
J Endocrinol
; 237(2): 165-173, 2018 05.
Article
en En
| MEDLINE
| ID: mdl-29549187
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 growth hormone (GH) regulation by examining the effect of kisspeptin antagonists on 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 ovariectomized 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 GH secretion through GPR54 expressed on somatotropes.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Hormona del Crecimiento
/
Kisspeptinas
/
Antagonistas de Hormonas
Límite:
Animals
Idioma:
En
Revista:
J Endocrinol
Año:
2018
Tipo del documento:
Article
País de afiliación:
Australia