PROSTAGLANDIN SYNTHESIS IN THE ENDOMETRIUM OF WOMEN WITH OVULAR DYSFUNCTIONAL UTERINE BLEEDING

Abstract

Summary: The endogenous concentrations of prostaglandins F 2α (PGF 2α) and E (PGE) were measured during the luteal phase of the menstrual cycle in the endometrium from 14 women with unexplained menorrhagia (measured menstrual blood loss in excess of 50 ml) and 15 women with normal menses (blood loss 50 ml or less). Although there was no significant difference in the PGF 2α/PGE ratio between the two groups, this ratio was significantly lower in the endometrium from eight of the women whose blood loss exceeded 90 ml (p <0.05). There was a significant inverse correlation between the PGF 2α/PGE ratio and blood loss (r = 0.36, p <0.025). The synthetic capacity of the endometrium was assessed by incubation of the tissue with 14 C arachidonic acid. Endometria from nine women with unexplained menorrhagia synthesized more PGE 2 than PGF 2α, whereas the converse was true with 11 control endometria. Consequently the PGF 2α/PGE 2 ratio was significantly reduced in the former group (p <0.025). Oestradiol‐17β (200 μM) and to a greater extent 2 hydroxy oestradiol (200 μM) increased the total prostaglandin synthesis by the endometria, but did not significantly alter the PGF 2α/PGE 2 ratio. These results suggest that excessive blood loss may be associated with a shift in the endometrial conversion of prostaglandin endoperoxide from PGF 2α to PGE 2.