Quantitative analysis of estrogen receptor alpha and beta messenger ribonucleic acid levels in normal endometrium and ovarian endometriotic cysts using a real-time reverse transcription-polymerase chain reaction assay

Objective: To quantify messenger RNA (mRNA) levels of the two estrogen rece ptor isoforms, estrogen receptor-alpha (ER-alpha) and estrogen receptor-bet a (ER-beta) in the eutopic endometrium and ovarian endometriotic cysts. Design: Prospective study. Setting: University hospital. Patient(s): Patients with endometriosis and patients with uterine leiomyoma or carcinoma in situ. Intervention(s): Gonadotropin-releasing hormone agonist (GnRH-a)-treated (n = 12) or untreated (n = 24) endometriotic cysts were obtained from 36 pati ents during laparoscopic cystectomy. Eutopic endometrium tissues were obtai ned from 24 patients during or immediately after surgery. Main Outcome Measure(s): ER-alpha and ER-beta mRNA levels, using a real-tim e reverse transcription (RT)-polymerase chain reaction (PCR) assay, TaqMan RT-PCR. Result(s): Eutopic endometrium and ovarian endometriotic cysts showed predo minantly higher levels of ER-alpha mRNA than ER-beta mRNA. Although ER-alph a and ER-beta mRNA levels in the eutopic endometrium were affected by a cyc lic change in ovarian hormones, ovarian endometriotic cysts were less affec ted. Moreover, a long-term hypoestrogenic state induced by GnRH-a especiall y decreased ER-alpha mRNA levels in endometriotic cysts. Consequently, the relative ratios of ER-alpha to ER-beta mRNA levels in both GnRH-a-treated a nd untreated endometriotic cysts were significantly lower than those in the eutopic endometrium. Conclusion(s): The results suggest that the principal and regulatory effect s of estrogens may be mediated mainly via ER-alpha rather than ER-beta in b oth the eutopic endometrium and endometriotic cysts. (Fertil Steril (R) 200 0;74:753-9. (C) 2000 by American Society for Reproductive Medicine.).