The activity of calcium dependent and calcium independent phospholipase A2 in normal endometrium and in endometrium from women suffering from menorrhagia and polycystic ovary syndrome

Abstract

The activity of 2 phospholipase A2 enzymes, PLA2(i) and PLA2(ii) was measured in endometrium in women with regular menstrual cycles without evidence of pathology and in those complaining of menstrual disturbances.

There was a significant 4-fold increase in PLA2(i) activity in secretory phase endometrium (mean ± SD: 32.7 ± 9.5 pmol per mg protein/minute) compared to that of the proliferative and menstrual phases (9.5 ± 4.9 and 6.1 ± 2.6 pmol per mg protein/minute, respectively) but PLA2(ii) activity was variable and not related to the stage of the cycle (range: 4.0-97.0, 18.7-110.3 and 0.1-85.5 pmol per mg protein/minute for proliferative, secretory and menstrual phases, respectively). There was no significant difference between normal subjects and those with menorrhagia with respect to the mean activities of either isoenzyme at any stage of the cycle. Women with polycystic ovary syndrome (PCO) had markedly higher endometrial PLA2(ii) activity than normal subjects.

The evidence of this study suggests that PLA2(ii) is not implicated in unexplained menorrhagia, but our preliminary findings indicate that the high level of PLA2(ii) activity found in the endometrium of women with PCO might be a marker of abnormal endometrial function.