CHARACTERIZATION OF SUBCELLULAR MEMBRANE-FRACTIONS FROM WHITE ADIPOSE-TISSUE OF OBESE MICE

Subcellular membrane fractions of white adipose tissue (WAT) from obese aurothioglucose- (AuTG) and monosodium glutamate- (MSG) treated mice, as well as from normal age matched mice, have been examined. Fat pad weight and adipocyte size increased greatly up to 12 folds in obese mice. A cellular fractionation of WAT was performed to obtain fat free extract (FFE), plasma membrane (PM) and microsomal (M) subcellular fractions. Protein recovery in FFE, related to the tissue weight, was 3 folds reduced in obese mice. However, protein recoveries of PM and M (over the FFE content) did not change. 5'nucleotidase activity (plasma membrane marker) showed no different specific activity in all subcellular fractions among the groups. In addition, total enzyme activity recovered in PM, expressed by unity of cell surface area, did not change among different animals. We conclude that, in obese mice, although severe morphological changes occur, the cellular fractionation, as performed here, did not interfere with subcellular membrane fractions characteristics.