The administration of estrogens to man produces sustained elevation above normal levels of plasma (1, 2). The elevated levels of plasma 17-OHCS are associated with an augmented response of plasma levels of these steroids to exogenous adrenocorticotropic hormone (ACTH) and with a marked delay in the rate of clearance of exogenous cortisol from plasma (2). The last trimester of pregnancy is associated with similar changes in levels of plasma 17-OHCS and in their response to exogenous ACTH (3-9). In the last trimester of pregnancy there is a variable increase in urinary 17-OHCS excretion, a decrease in the rate of clearance of exogenous cortisol from plasma (9-11), a decrease in the rate of clearance of exogenous tetrahydrocortisone from plasma (11) and an increase in corticosteroid-binding protein (12). The apparently normal adrenal status of pregnant women and of patients treated with estrogens for long periods of time suggests that the administration of estrogens to man elevates plasma 17-OHCS levels by altering the normal metabolism of endogenous cortisol by a mechanism similar to that seen in pregnancy. Studies have been made of urinary 17-OHCS excretion, of clearance of tetrahydrocortisone from plasma, and of plasma corticosteroid-binding protein after the administration of estrogens to man.
MATERIALS AND METHODSThe patients studied were primarily adult females ranging in age from 37 to 75 years, all of whom either had been surgically castrated or were at least 3 years past a spontaneous menopause. A number of these subjects were patients with metastatic carcinoma of the * This work was supported in part by a research grant from The National Cancer Institute, Bethesda, Md. breast. One male was studied during recovery from a myocardial infarction.After appropriate control studies, the patients were treated for periods of 2 weeks to 6 months with either oral ethinyl estradiol (Estinyl), diethylstilbestrol or conjugated equine estrogens (Premarin). Only doses of these preparations which uniformly elevated plasma 17-OHCS levels above normal were used in the studies (Table I). Ethinyl estradiol 0.1 and 0.5 mg, diethylstilbestrol 15 mg, and Premarin 10 mg, daily by mouth, all caused significant increases in the levels of plasma 17-OHCS.The effect of oral ethinyl estradiol, 0.5 mg daily, on urinary excretion of free and total 17-OHCS and of 17-ketosteroids was studied. Twenty-four hour urinary excretion of steroids was determined in each patient before estrogen therapy and again after plasma 17-OHCS