Prolactin stimulates adrenal androgen secretion in infant baboons

It has been suggested that pituitary factors other than ACTH modulate adrenal steroidogenesis during maturation of the pituitary-adrenocortical axis. Therefore, we determined whether hormones other than ACTH influence the production of cortisol (F), dehydroepiandrosterone (DHA), and DHA-sulfate (DHAS) in baboon infants studied between 8 and 24 months of age. Animals (three males, two females) were sedated with ketamine and peripheral blood samples taken 20, 10, and 0 min before a 90-min constant iv infusion of 448 pmol/min of either ACTH, ovine PRL, ovine GH, 2.4 nmol/min human CG (hCG), or normal saline. Serum F, DHA, and DHAS concentrations of blood samples obtained during the infusion (70, 80, 90 min) were averaged and compared with average pretreatment values. Each animal received each of the treatment protocols which included a minimum recovery period of 3-6 weeks. The serum concentrations of F, DHA, and DHAS did not vary with age and averaged (mean +/- SE) 24 +/- 2, 1.9 +/- 0.2, and 36 +/- 5 micrograms/dl, respectively. Compared to pretreatment values, ACTH increased (P less than 0.05) mean serum F concentrations by 155 +/- 20%; PRL, GH, hCG, and saline had no effect. In contrast, serum DHA concentrations were stimulated (P less than 0.05) by both ACTH (131 +/- 20%) and PRL (58 +/- 18%); GH, hCG, and saline had no effect. Similar findings were observed for serum DHAS concentrations. These findings indicate that the majority of serum androgens in young baboons is of adrenal origin. Therefore, we conclude that PRL, in addition to ACTH, may also be an adrenocorticotrophic factor in baboon infants. However, in contrast to ACTH, the action of PRL on the adrenal is apparently specific for androgen production.