Van Pelt, Rachael E.Gozansky, Wendolyn S.Hickner, Robert C.Schwartz, Robert S.Kohrt, Wendy M.2011-01-282011-05-162011-01-282011-05-162006-12Obesity (Silver Spring); 14:12 p. 2163-2172http://hdl.handle.net/10342/3141Objective: The aim of this study was to determine whether intravenous (IV) conjugated estrogens (EST) acutely enhance the suppression of whole-body or regional subcutaneous adipose tissue (SAT) lipolysis by insulin in postmenopausal women. Research Methods and Procedures: We assessed whole-body lipolysis by [2H5]glycerol rate of appearance (GlycRA) and abdominal and femoral SAT lipolysis (interstitial glycerol; GlycIS) by subcutaneous microdialysis. Postmenopausal women (n = 12) were studied on two occasions, with IV EST or saline control (CON), under basal conditions and during a 3-stage (4, 8, and 40 mU/m2/ min) hyperinsulinemic, euglycemic clamp. Ethanol outflow/inflow ratio and recovery of [13C] glycerol during microdialysis were used to assess blood flow changes and interstitial glycerol concentrations, respectively. Results: Compared with CON, EST did not affect systemic basal or insulin-mediated suppression of lipolysis (GlycRA) or SAT nutritive blood flow. Basal GlycIS in SAT was reduced on the EST day. However, insulin-mediated suppression of lipolysis in SAT was not significantly influenced by EST. Discussion: These findings suggest that estrogens acutely reduce basal lipolysis in SAT through an unknown mechanism but do not alter whole-body or SAT suppression of lipolysis by insulin. Originally published Obesity (Silver Spring), Vol. 14, No. 12, Dec 2006en-USAuthor notified of opt-out rights by Cammie JenningsSubcutaneous adipose tissueAbdominalFemoralInterstitial glycerolPostmenopausal womenArticlePMC283260810.1038/oby.2006.253