Expression of messenger ribonucleic acid for gonadal steroid receptors in the human pelvic peritoneum

Objective To investigate the expression of messenger RNA (mRNA) for gonadal steroid hormone receptors in the human pelvic peritoneum. Design Analysis of estrogen receptor (ER), progesterone receptor (PR), and androgen receptor (AR) mRNA expressions in the pelvic peritoneum was carried out using the quantitative reverse transcription-polymerase chain reaction (PCR) method. Setting Department of Gynecology and Obstetrics, Kyoto University Hospital, Kyoto, Japan. Patients Pelvic peritoneal tissues from patients with (n = 10) and without (n = 10) endometriosis who had undergone gynecological surgery were studied. Results Estrogen receptor, PR, and AR mRNAs were detected in all pelvic peritoneal samples analyzed. In the pelvic peritoneum of patients without endometriosis, ER mRNA levels were significantly lower in the luteal phase than in the follicular phase. This cyclic profile of ER mRNA expression was not observed in the pelvic peritoneum of patients with endometriosis. During the follicular phase, ER mRNA levels in the pelvic peritoneum of patients with endometriosis were significantly lower than those of patients with endometriosis. Neither PR nor AR mRNA levels in the pelvic peritoneum of either patient group showed significant cyclic variations throughout the menstrual cycle. A comparison of PR and AR mRNA levels in the pelvic peritoneum of the endometriosis and the nonendometriosis groups revealed no significant differences. Conclusions These data indicate a decrease in ER gene expression in the pelvic peritoneum of patients with endometriosis during the follicular phase. This suggests that the possible responsiveness of peritoneal cells to estrogen may be related to the occurrence and/or development of endometriosis.