The effects of delayed hormone replacement therapy on estrogen receptors of the cynomolgus monkey bladder and vagina.

Abstract

The aim of this study was to determine cytosolic estrogen receptor content of the cynomolgus monkey bladder and vagina after hormone replacement therapy. Animals maintained without hormone therapy for 2 years after surgical menopause were randomized to receive either no hormones (OVX), conjugated equine estrogens (CEE), or estrogen/medroxyprogesterone acetate (CEE + MPA) treatment for 30 months. Estrogen receptor content of bladder and vagina cytosolic extracts was determined using a commercial enzyme-linked immunosorbent assay. Estrogen receptors were uniformly present, although the vaginal concentration was 100-fold greater than in the bladder. Estrogen and combination therapy significantly decreased cytosolic receptor content in both sites compared with controls. The cynomolgus urogenital tract remains estrogen sensitive 2 years after surgical menopause. Prolonged exposure to estrogens decreases cytosolic estrogen receptor content in a manner similar to that described for short-term estrogen therapy. These results suggest that the effects of hormone replacement on the urinary tract can be identified even if initiated years after menopause.