Endometrial and Myometrial Prostaglandin Release during the Menstrual Cycle in Relation to Menstrual Blood Loss*

Abstract

Endometria and myometria were collected at hysterectomy from 42 women with measured menstrual blood loss. Specimens were obtained throughout the menstrual cycle [menstrual (n = 11), follicular (n = 9), early luteal (n = 6), midluteal (n = 9), and late luteal (n = 7)]. In vitro endometrial and myometrial release of prostaglandin F2 alpha (PGF2 alpha), PGE2, and 6-keto-PGF1 alpha were examined using a superfusion technique. In the endometrium, the principal PG produced was PGF2 alpha, while in the myometrium, it was 6-keto-PGF1 alpha. Cyclical changes in PG release were found only in the endometrium, with an increase toward the end of the menstrual cycle and during menstruation. No significant correlation was found between menstrual blood loss (range, 4-840 ml) and PGF2 alpha, PGE2, or 6-keto-PGF1 alpha release in either endometrium or myometrium. Furthermore, there was no correlation between either the PGF2 alpha to PGE2 or the PGF2 alpha to 6-keto-PGF1 alpha ratios and menstrual blood loss.