Growth hormone stimulates adrenal steroidogenesis in the fetus

Publisher Website
Google Scholar
Abstract
The surge of corticosteroid in fetal plasma during late gestation was implicated in the initiation of parturition and the maturation of enzyme systems in organs such as the lung, liver, adrenal medulla and thyroid. But in all species studied, the mechanism responsible for increased secretion in the fetus remains unclear. ACTH is well established as the primary regulator of adrenocortical cellular growth and secretory function during fetal and adult life. No increase in fetal plasma ACTH was observed before the corticosteroid surge in sheep or humans, although differential responsiveness of the fetal adrenal cortex to ACTH at various gestational ages and a possible role of extra-adrenal inhibitory factors were proposed. The possible steroidogenic effect of .alpha.-melanocyte-stimulating hormone on fetal adrenocortical function is controversial; no such action was demonstrated in fetal lamb or rabbit. Prolactin and growth hormone (GH) potentiate the steroidogenic effect of ACTH in adult rats but prolactin had no such effect in fetal lamb. The steroidogenic properties of GH were investigated. It stimulates adrenal steroidogenesis in the fetal but not maternal rabbit in vitro and in fetal but not maternal sheep in vitro and in vivo.