Comparative immunohistochemical study of oestrogen and progesterone receptors in the fallopian tube and uterus at different stages of the menstrual cycle and the menopause.

Oestrogen and progesterone are known to require their corresponding steroid receptors to manifest structural and functional effects in the Fallopian tube, uterus and other target organs. This study compares cyclical variations of these receptors in the uterus and in different segments of the Fallopian tube in the same subjects using an immunocytochemical technique. The results show that in the Fallopian tube, isthmic and ampullary epithelial and stromal oestrogen receptors increased in the follicular phase to a peak at mid cycle and then declined in the late luteal phase. The intensity of immunostaining of oestrogen receptors was less in the Fallopian tube than in endometrial glandular epithelium. The fimbrial end demonstrated an opposite pattern of staining to other segments of the tube. Progesterone receptor immunostaining was more intense than that for oestrogen receptors in the follicular phase, and, whereas it disappeared completely from the endometrial glandular epithelium in the late luteal phase, positive staining was clearly visualized in the tubal epithelium and stroma and endometrial stroma at this stage of the menstrual cycle. These differences in the steroid receptor content may reflect the changing and different functional roles of these regions and may have important implications on human reproduction.