Obesity in obese-hyperglycaemic mouse is associated with an increase in number and size of adipocytes. Adipocytes from the obese mouse showed increased incorporation of [14C]acetate and[14C]glucose into triacylglycerol. This increased capacity of triacylglycerol formation was correlated with increased activities of various triacylglycerol-forming enzymes measured in the microsomal fraction of adipose tissue from obese mice. Microsomal fractions from lean and obese mice contained sn-glycerol 3-phosphate acyltransferase, phosphatidate phosphohydrolase and diacylglycerol acyltransferase. Phosphatidate phosphohydrolase was also detected in the soluble fraction. In the presence of Mg2+, the phosphatidate phsophohydrolase from the soluble and the microsomal fractions was active towards membrane-bound phosphatidate. Among the three enzymes studied here, the increase in Mg2+-dependent phosphatidate phosphohydrolase was most prominent in adipose tissue of obese mice.
