Effects of endothelin-1 and endothelin-3 on rat hypothalamic corticotrophin-releasing hormone and pituitary ACTH release in vitro

Endothelins (ETs) are potent vasoconstrictor peptides that also participate in the regulation of endocrine function. Indeed, immunoreactive ET, ET mRNA and ET receptors have been found in the brain and the pituitary gland and ETs stimulate arginine vasopressin, LH, FSH, TSH and gonadotrophin-releasing hormone and inhibit prolactin release in vitro. The present study was undertaken to evaluate the effects of ET-1 and ET-3, two members of this family, on corticotrophin-releasing hormone (CRH) release by explanted male rat hypothalami in vitro and on ACTH release by primary pituitary cell culture. ET-3 decreased basal CRH release in a concentration-related manner. The lowest effective concentration tested was 3 nmol/l but a more pronounced inhibitory effect was obtained at a concentration of 10 nmol/l