Glucose-induced thermogenesis in obese subjects with or without familial history of obesity.

In order to assess to what extent familial factors play a role in thermogenesis of obese individuals, the 3 h response to a 100 g glucose oral load was measured in 11 obese subjects (6 m, 5 f) with a familial history of obesity and/or obesity-non-insulin dependent diabetes mellitus (NIDDM, group A); these were compared to 9 obese subjects (5 m, 4 f) without familial history of these disorders (group B). All subjects had normal glucose tolerance and the two groups were comparable with respect to anthropometric features. The glucose-induced thermogenesis of group A (7.9 +/- 1.2 per cent) above preload energy expenditure was significantly lower (P less than 0.01) than that observed in group B (13.5 +/- 0.5 per cent). The same conclusions were obtained when the results were expressed as a percentage of the glucose load ingested (4.4 +/- 0.67 and 7.8 +/- 0.80 in group A and group B respectively, P less than 0.01). Despite these differences the pattern of change in glycaemia, insulinaemia, C-peptidaemia and glucagonaemia in response to the glucose load was the same between the two groups. Total glucose oxidation as well as non-oxidative glucose disposal did not differ between the two groups. These results seem to support the hypothesis that genetic factors may contribute to the low thermogenic response observed in some individuals with a familial history of obesity and/or obesity-NIDDM.