DIFFERENCES IN THE ESTROGEN CONTENT OF BREAST ADIPOSE-TISSUE IN WOMENBY MENOPAUSAL STATUS AND HORMONE USE

Objective: To determine the levels of free estrone (E1) and estradiol (E2) in breast adipocytes of premenopausal women, premenopausal women using oral contraceptives (OCs), postmenopausal women, and postmenopau sal women using estrogen replacement therapy (ERT). Methods: Breast ad ipose tissue was obtained from 36 premenopausal and 29 postmenopausal women, and adipocytes were separated from stromal and epithelial cells through collagenase digestion and centrifugation. Oil was rendered fr om adipocytes, and E1 and E2 levels were measured by specific radioimm unoassays after extraction with methanol-water. Results: Estrone and E 2 levels were approximately 2.4- and 7.8-fold higher, respectively, in premenopausal women than in postmenopausal women. In premenopausal wo men, E1 and E2 correlated with the time since last menses (R-2 = .55 a nd .62, respectively), whereas in postmenopausal women, E1 and E2 corr elated with body mass index (BMI) (r = .48 and .52, respectively). Est rone levels were always greater than E2 levels in adipocytes, with the E1/E2 ratio being 2.7-fold higher in postmenopausal women than in pre menopausal women. The use of OCs decreased E1 and E2 levels in premeno pausal women, and ERT increased levels in postmenopausal women. Conclu sion: Free estrogen in breast adipocytes is characterized by E1 domina nce, with levels in premenopausal women correlating with the menstrual cycle and levels in postmenopausal women correlating with BMI. (C) 19 97 by The American College of Obstetricians and Gynecologists.