Figure 1. Synthesis of sex steroids. Androgens are steroids that stimulate the development of male secondary sex characteristics. In nonpregnant women, androgens and their precursors are produced by both the adrenal glands and the ovaries in response to their respective tropic hormones: corticotropin (ACTH) and luteinizing hormone (LH). In the ovaries, androgens are produced as precursors in the synthesis of estrogen and estradiol. The theca cells of preantral (secondary) ovarian follicles produce androstenedione and testosterone in response to luteinizing hormone. In response to follicle-stimulating hormone (FSH), the granulosa cells aromatize these androgens to the estrogens. CRF = corticotropin-releasing factor, LH-RH = luteinizing hormone-releasing hormone.