Evidence for cycle-dependent expression of follicle-stimulating hormone receptor in human endometrium

Objective. It was the purpose of the present study to investigate whether human endometrium expresses follicle-stimulating hormone (FSH) receptor mRNA and peptide, and whether this expression is regulated in a cycle-dependent manner in endometrium derived from various phases of the menstrual cycle. Methods. FSH receptor mRNA and peptide expression were evaluated by reverse transcription-polymerase chain reaction and by immunohistochemistry in endometrium from 15 women undergoing hysteroscopy to evaluate the morphology of the uterine cavity or hysterectomy for leiomyomas. Results. FSH receptor mRNA was expressed by human endometrium, and its peptide was located immunohistochemically in both proliferative and secretory endometrial epithelial and stromal cells. A significant increase in immunoreactive FSH receptor was observed during the secretory phase. Conclusions. We have shown the presence of FSH receptor in human endometrium and demonstrated that FSH receptor immunostaining is upregulated in the secretory phase of the menstrual cycle. The dynamic pattern of receptor expression indicates that FSH may play a role in the regulation of endometrial function and possibly in the embryo-endometrium interaction.