Figure 1: Production of sex steroids from the adrenal precursors, dehydroepiandrosterone (DHEA) and its sulfate form (DHEAS). DHEA, an inactive prohormone, is produced by the adrenal glands from cholesterol. DHEA and DHEAS are interconvertible by the actions of sulfatases and sulfotransferases. In peripheral tissues, the hydroxysteroid dehydrogenases (HSD) convert DHEA to androstenedione and androstenediol, precursors of testosterone. The action of 5a-reductases converts testosterone to its potent metabolite, dihydrotestosterone (DHT). Aromatases produce estrogens by converting testosterone to estradiol and androstenedione to estrone.