Studies on the Mechanism of the Plasma 17-hydroxy- Corticosteroid Elevation Induced in Man

The administration of estrogens to man produces sustained elevation above normal levels of plasma 17-hydroxycorticosteroids (17-OHCS) (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.