Prostaglandin F2 alpha and E2 in primary dysmenorrhea: myometrial sensitivity to PGF2 alpha and PGE2 in dysmenorrhea.

The sensitivity of myometrium to intrauterine administration of prostaglandin F2 alpha (PGF2a) and PGE2 was evaluated in 5 dysmenorrheic women during the secretory phase and during menstruation. In addition the effect of oral doses of 1 mg of PGE2 was studied in 3 dysmenorrheic and 7 nondysmenorrheic women on the 1st and 2nd day of menstruation. Effects of placebo and naproxen (prostaglandin synthetase inhibitor) on uterine contractility during dysmenorrheic pain were also studied in 6 patients. Placebo was administered 30 minutes after the start of the recording when the contractility pattern was stabilized and 1 hour later naproxen tablets were given (250-500 mg). During intrauterine administration myometrial sensitivity showed 4 cases responding with stimulation after 2 mcg and 1 after 5 mcg of PGF2a; for PGE2 a complex pattern was obtained with both a stimulatory response after 1 and 5 mcg and an inhibitory effect after 20 and 37 mcg. 1 mg of PGE2 administered orally led to inhibition of uterine contractility in 4 of 7 eumenorrheic women and in 2 of 3 dysmenorrheic subjects. Naproxen administration (250 mg orally) caused a decrease in tonus from 20-0 55-50 and 30-0 mm of mercury within 2 hours. A more rapid decrease in tonus was observed within 1 hour after the 500 mg dose. A reduction of tonus to zero occurred in all 3 cases given 500 mg after 2 hours. (Placebo had no effect on tonus.) The sensitivity of the myometrium to intrauterine administration of PGF2a did not differ between normal and dysmenorrheic women.