Prostaglandin secretion by human endometrium in vitro.

Late proliferative (days 9 to 14) and midsecretory (days 18 to 24) human endometria were maintained in organ culture in the presence of 17 beta-estradiol and/or progesterone or mefenamic acid 17 beta-estradiol (0.1 to 1,000 ng/ml) increased prostaglandin F (PGF) secretion by both proliferative and secretory endometria. Progesterone (1,000 ng/ml) markedly inhibited PGF secretion by proliferative but not secretory endometrium. 17 beta-estradiol and progesterone had no effect on prostaglandin E (PGE) secretion by both types of endometrium. Secretion of both PGF and PGE by proliferative and secretory endometria was inhibited by mefenamic acid ( 1 microgram/ml). This was more apparent with PGF secretion and was detectable within the first 2 hours of culture. These findings indicate that the human endometrium is a rich source of PGF and PGE and that the production of PGF is regulated by gonadal steroids. These results support the concept that one mechanism of action of mefenamic acid in the treatment of dysmenorrhea is inhibition of prostaglandin production.