The biological expression of natural progesterone

Progesterone tablets were orally administered to women with no recent luteal activity. Three hypoestrogenic subjects who received, respectively, a single dose of 150 mg, 300 mg and 300 mg/d/7d, showed absorption and a progressive increase in circulating values in a dose-dependent manner. Five out of nine oligomenorrheic patients experienced withdrawal uterine bleeding with 150 mg/12/5d. Postmenopausal endometrium estrogenised by mestranol (n = 5) showed secretory histological changes after 300 mg/d/7d of oral progesterone. Six women with luteal insufficiency received 300 mg/d after control studies, and this dosage was effective in supplementing the circulating natural hormone so that it reached the level of that of fertile women. However, the endometrial progesterone uptake of these women showed no parallel increase. This study supports the clinical usage of oral progesterone and suggests evaluation of the dynamics of hormone uptake by the reproductive tissues.