Masazumi Iwai

Immunohistochemical localization of oestrogen receptors and progesterone receptors in the human ovary throughout the menstrual cycle

Immunohistochemistry was used to determine the distribution of oestrogen receptors (ER) and progesterone receptors (PR) in the human ovary during folliculogenesis. Primordial and preantral follicles did not contain ER or PR. The granulosa cells of antral follicles had ER, but negligible PR, before the LH surge. In contrast, at the time of LH surge, these cells of the dominant follicle contained PR, but not ER. On the other hand, granulosa cells of the non-dominant follicles had ER, but not PR. After ovulation, the PR persisted in the luteinized granulosa cells and in the corpus luteum during early pregnancy. The theca interna and surrounding stromal cells were ER-negative and PR-positive throughout the menstrual cycle. Thus, the results show that ER and PR are not expressed simultaneously in the granulosa cells, the thecal cells, or the stromal cells during folliculogenesis. Mechanisms controlling the expression of steroid receptors during the normal menstrual cycle and in early pregnancy are discussed.

Immunohistochemical Study of a Rat Membrane Protein which Induces a Selective Potassium Permeation: Its Localization in the Apical Membrane Portion of Epithelial Cells

SummaryWe previously reported a novel rat membrane protein that exhibits a voltage-dependent potassium channel activity on the basis of molecular cloning combined with an electrophysiological assay. This protein, termedIsK protein, is small and different from the conventional potassium channel poroteins but induces selective permeation of potassium ions on its expression inXenopus oocytes. In this investigatiion, we examined cellular localization of ratIsK protein by preparing three different types of antibody that specifically reacts with a distinct part of ratIsK protein. Immunohistochemical analysis using these antibody preparations demonstrated that ratIsK protein is confined to the apical membrane portion of epithelial cells in the proximal tubule of the kidney, the submandibular duct and the uterine endometrium. The observed tissue distribution of ratIsK protein was consistent with that of theIsK protein mRNA determined by blot hybridization analysis. In epithelial cells the sodium, potassium-ATPase pump in the basolateral membrane generats a sodium gradient acrossthe epithelial cell and allows sodium ions to entere the cell through the apical membrane. Thus, taking into account the cellular localization of theIsK protein, together with its electrophysiological properties, we discussed a possible function of theIsK protein, namely that this protein is involved in potassium permeation in the apical membrane of epithelial cells through the depolarizing effect of sodium entry.

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.

Human Decidual Function in Trophoblast and Uterine Interaction

The decidua constitutes an anatomical compartment of the placenta in deciduate mammals including humans. By virtue of its anatomical location at the interface between maternal and fetal tissues, it has long been recognized that the decidua possesses a particular function which leads to the formation of an immunologically privileged site to accommodate the semi-allograft implant and its subsequent development.