Synthesis of postmenopausal estrogens. Postmenopausal estrogens are synthesized from androgens (i.e., testosterone and androstenedione). In females, androgens are produced in the ovaries and the adrenal glands. They are transported in the bloodstream to body fat, where androstenedione is converted to estrone. Estrone replaces estradiol as the primary estrogen after menopause.