The rate of oxidation of [1-14C]glucose to 14CO2 was examined in subcutaneous adipose tissue from fifteen obese non-diabetic subjects and from eleven obese maturity-onset diabetic patients. Production of 14CO2, measured in the basal state and in the presence of insulin, was significantly correlated with mean cell size in both the non-diabetic and the diabetic subjects, independent of age, relative weight and fasting plasma insulin concentration. 2. Comparison of the regressions of glucose oxidation rates on mean cell size indicated: (i) that insulin produced a significant increase in activity over the basal value in both groups, and (ii) that basal and insulin-stimulated activity were both significantly lower in diabetic than in non-diabetic adipose tissue.
