The role of endogenous postmenopausal androgens on abdominal FAT distribution

Abstract

OBJECTIVE: In men, androgens have beneficial effects on a wide range of metabolic and morphometric indices, including patterns of fat deposition. In postmenopausal women, testosterone (T) replacement has been shown to enhance sexual function, but little is known about its other possible benefits in this population. It is commonly assumed that androgens are associated with adverse metabolic patterns of abdominal fat distribution in this population, with increased visceral fat. The objective of this study was to determine the relationship between postmenopausal androgen levels and regional body composition in normal weight postmenopausal women. Our hypothesis was that higher postmenopausal circulating testosterone (T) levels are not associated with adverse alterations in regional adiposity in this population. DESIGN: Academic research center. MATERIALS AND METHODS: A total of 38 healthy, 50-70 year old, nonsmoking, nonhirsute, normal weight (BMI< 28) postmenopausal (>3 years, FSH >50 mIU/ml) women participated. 29 women had natural and 9 women had surgical menopause. They had been on no hormone replacement therapy, no history of infertility, cycle irregularity, or hyperandrogenemia. Total, subcutaneous, and visceral abdominal fat was calculated using computed tomography (CT) scan at the L4-L5 level. Fasting serum T, free T, androstendione (Δ4A), estradiol (E2), and dehydroepiandrosterone sulfate (DHEAS) levels were batch assayed using radioimmunoassays with preassay chromatographic separation, validated for the low levels seen in this population. Sex hormone binding globulin (SHBG) was measured with direct chemiluminescent immunoassay. Correlations between subcutaneous, visceral, and abdominal fat with these serum markers were performed by using Pearson correlation coefficients. RESULTS: There were no significant correlations between T or E2 levels with any aspect of regional body composition. However, increasing FT, Δ4A, and DHEAS levels positively correlated to subcutaneous fat (R=0.324, 0.348, 0.398; p<0.05, respectively). These changes were seen in both surgical and natural menopause patients. CONCLUSIONS: In healthy normal weight postmenopausal women without a history of PCOS, higher endogenous Δ4A, DHEAS, and FT levels were related to higher levels of subcutaneous fat, but not with increases in visceral fat. These relationships suggest that, in this population, elevations of circulating androgens within the physiologic range do not adversely impact patterns of regional fat deposition.