Immunohistochemical localization of pituitary gonadotropins and estrogen in human postmenopausal ovaries

Immunohistochemical localization of pituitary gonadotropins (FSH, LH) and estrogen was investigated in 17 ovaries from ten postmenopausal women. Positive immunostaining for 17 beta-estradiol was demonstrated in the cortical stroma of 14 postmenopausal ovaries. Positive immunostaining for FSH was localized in the cortical stroma of 12 postmenopausal ovaries, and positive immunostaining for LH was also localized in 12 ovaries. Immunohistochemical localization for pituitary gonadotropins (FSH and/or LH) and 17 beta-estradiol was identified in the same hypertrophic cortical stroma of 13 postmenopausal ovaries. The ultrastructural study suggested steroidogenic activity in the cortical stromal cells of the postmenopausal ovary. In addition, peripheral and ovarian venous concentrations of 17 beta-estradiol were measured in 13 postmenopausal subjects, and significant concentration gradient for serum 17 beta-estradiol was noted. The ovarian/peripheral concentration gradient for 17 beta-estradiol had a tendency to be higher in the subjects with positive immunostaining for 17 beta-estradiol compared with that in the subjects with negative immunostaining. The present results suggest that the human ovary secretes estrogen in response to pituitary gonadotropins even after the menopause.