Fig. 1. Principal pathways of androgen synthesis and catabolism. Enzymes: (1) 3β-hydroxysteroid dehydrogenase; (2) 17β-hydroxylase; (3) 17,20-lyase; (4) 17β-hydroxysteroid dehydrogenase; (5) aromatase; (6) 5α-reductase; (7) 5β-reductase; (8) 3β-oxoreductase; (9) 3α-reductase. A. In the gonads, the 17β-hydroxysteroid dehydrogenase activity predominantly yields 17β-dehydrogenated products (androstenediol and testosterone), whereas the reverse is true in peripheral tissues. B. Aldosterone, etiocholanolone, and dehydroepiandrosterone (DHEA) are the principal urinary metabolites of androgens. (Azziz R: Reproductive endocrinologic alteration in female asymptomatic obesity. Fertil Steril 52:703, 1989)