The physiological role of the adrenal androgens seems to be relatively small. Those adrenal androgens are converted by peripheral tissues into testosterone and estradiol, whereas conversion within the adrenal cortex is minimal. The zona reticularis produces androgens such as dehydroepiandrosterone (DHEA), its sulfate analog DHEA sulfate, and androstenedione as well as glucocorticoids. The zona fasciculate is the thickest layer and produces glucocorticoids (cortisol and corticosterone) and androgens. The zona glomerulosa produces mineralocorticoids (mainly aldosterone) and as it lacks 17α-hydroxylase activity it cannot produce cortisol or androgens. The zona fasciculate and reticularis appear to function as a single unit. The surrounding cortex arises from mesoderm and is composed of 3 zones: an outer zona glomerulosa, a zona fasciculate, and an inner zona reticularis. The medulla, which is of neuroectodermal origin, comprises approximately ¼ of the adrenal mass and secretes norepinephrine and epinephrine. The adrenal gland consists of two functionally distinct endocrine glands of different embryological origin.
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