Progesterone Receptor Isoform A But Not B Is Expressed in Endometriosis

作者：George Roshdy Attia · 发表于：The Journal of Clinical Endocrinology & Metabolism · 年份：2000 · DOI：10.1210/jc.85.8.2897 · 被引用次数：492 · 研究领域：Endometriosis Research and Treatment、Estrogen and related hormone effects、Reproductive System and Pregnancy

We previously demonstrated that 17beta hydroxysteroid dehydrogenase type 2, the enzyme that inactivates estradiol to estrone, is expressed in luteal eutopic endometrium in response to progesterone but not in simultaneously biopsied peritoneal endometriotic tissue. This molecular evidence of progesterone resistance, together with the clinical observation of resistance of endometriosis to treatment with progestins, led us to determine the levels of progesterone receptor (PR) isoforms PR-A and PR-B in eutopic endometrial and extra-ovarian endometriotic tissues. It was proposed that progesterone action on target genes is mediated primarily by homodimers of PR-B, whereas the truncated variant PR-A acts as a repressor of PR-B function. Immunoprecipitation, followed by Western blot analysis, was performed to detect bands specific for PR-A and PR-B in paired samples of endometriotic and eutopic endometrial tissues simultaneously biopsed from 18 women undergoing laparoscopy during various phases of the menstrual cycle. PR-B was present in 17 of 18 eutopic endometrial samples, and its level increased in the preovulatory phase, as expected, whereas PR-A was detected in all samples (n = 18) with a similar, but less prominent, cyclic variation in its levels. In endometriotic samples, however, no detectable PR-B could be demonstrated, whereas PR-A was detected in all samples (n = 18), albeit in much lower levels and without any cyclic variation in contrast with the eutopic endometrium. Lev...