Effects of Estrogen Therapy on Cortisol Metabolism

Abstract

Long-term, high-dose estrogen therapy was found to reduce the secretion rate of cortisol in normal female subjects. There were no marked changes in free cortisol in the urine. No evidence of any direct suppressive effect of estrogen on the adrenal cortex was found in these women, for response to stimulation by ACTH was unimpaired. Two female patients with Cushing's syndrome who were treated with large doses of estrogen failed to show significant biochemical or clinical improvement. In the normal subjects, diurnal variation and suppressibility of plasma cortisol by dexamethasone persisted despite high levels of total plasma cortisol during estrogen therapy. These tests of adrenal function can therefore still be used to rule out Cushing's syndrome, without discontinuing estrogen therapy.