ACTH and cortisol plasma levels in cancer patients treated with medroxyprogesterone acetate at high dosages.

The effects of medroxyprogesterone acetate (MPA) at high dosages on ACTH and cortisol plasma levels have been studied on seven patients which were carriers of ER+ and PR+ neoplasm. ACTH and cortisol plasma levels were studied at 8:00 a.m., before and after a 4-week treatment with MPA at dosages of 1000 mg/die at basal conditions and after a metyrapone stimulation test. The results obtained show that the MPA treatment causes a highly significant drop of both cortisol and ACTH plasma levels. The metyrapone stimulation test performed before and after MPA treatment confirms the suppressive effect of MPA on the hypothalamus-pituitary-adrenal gland axis. These data suggest a cortisol-like action of MPA with a negative feed-back mechanism on the hypothalamus-pituitary-adrenal gland axis.