Expression of estradiol and progesterone receptors by histologically normal endometria of women with postmenopausal bleeding

Abstract

Estradiol and progesterone receptor levels (RE2, RP) were measured in histologically normal endometria of women with postmenopausal bleeding (PMB) and the results were compared to those in histologically normal endometria of premenopausal and postmenopausal (PM) women and to those in pathological PM endometria. In histologically normal PMB endometria, RP levels were comparable to those in secretory premenopausal endometria and significantly higher than those in PM atrophic endometria. The RP levels in the former group correlated with the respective RE2 levels and the values of the ratio RP/RE2 occupied a mid-zone between those ratio values of normal premenopausal or pathological PM endometria on the one hand and normal PM endometria, on the other hand. The cytosolic/nuclear distribution of both receptor levels revealed that in both PMB and in pathological PM endometria, only a small fraction of the receptor was recovered in the nuclear extract. Expression of the RE2 and RP in the PMB and in the pathological PM endometria were associated with undetectable plasma E2 levels. These results indicate that histologically normal PMB endometria are biochemically active and suggest that endometrial growth and RE2, RP expression in PMB and pathological PM endometria are stimulated by a factor which acts distal to the RE2 acceptor.