Control of adrenal androgen secretion.

The human adrenal gland secretes large amounts of androgens and androgenic precursors as compared with the adrenal glands of other species. In part, this pattern of secretion is regulated by ACTH, analogous to the control of cortisol. However, in many instances, including adrenarche, puberty, aging, and severe illness, secretion of adrenal androgens and cortisol diverge for reasons which are not clear. Factors endogenous to the adrenal gland may have a role in the modulation of adrenal androgen secretion. These include the centripetal blood supply of the adrenal gland, availability of cofactors of steroidogenic enzymes, and intrinsic properties of adrenal cells or enzymes. However, these mechanisms may, in turn, be modified by factors exogenous to the adrenal gland. Possible evidence for a regulatory role for such known substances as growth hormone, IGF-1, gonadotropins, estrogens, angiotensins, prostaglandins, insulin, EGF, and POMC-related peptides is discussed. Furthermore, pituitary or extrapituitary substances, in addition to known hormones, may have a role in the control of adrenal androgen secretion. Several lines of evidence include the inability of ACTH to maintain a normal adrenal androgen/cortisol ratio in adrenally suppressed patients, or experimentally, in hypophysectomized chimpanzees. Evidence for such factors derived from fetal and adult human pituitary gland is discussed.