Glucose uptake and perfusion in subcutaneous and visceral adipose tissue during insulin stimulation in nonobese and obese humans

To elucidate the role of adipose tissue glucose uptake in whole-body metabolism, se and visceral adipose tissue glucose uptake and perfusion were measured in 10 nonobese and 10 age-matched obese men with positron emission tomography using [F-18]-2-fluoro-2-deoxy-D-glucose, and [O-15]-labeled water during normoglycemic hyperinsulinemia. Whole-body and skeletal muscle glucose uptake rates per kilogram were lower in obese than in nonobese subjects (P < 0.01). Compared with nonobese, the obese subjects had 67% lower abdominal sc and 58% lower visceral adipose tissue glucose uptake per kilogram of fat. In both groups, insulin stimulated glucose uptake per kilogram fat was significantly higher in visceral fat depots than in se regions (P < 0.01). Both sc and visceral adipose tissue blood flow expressed per kilogram and minute was impaired in the obese subjects, compared with the non- obese (P < 0.05). Fat masses measured with magnetic resonance images were higher in obese than in nonobese individuals. If regional glucose uptake rates were expressed as per total fat mass, total glucose uptake rates per depot were similar in obese and nonobese subjects and represented 4.1% of whole-body glucose uptake in obese and 2.6% in nonobese subjects (P < 0.02 between the groups). In conclusion, insulinstimulated glucose uptake per kilogram fat is higher in visceral than in se adipose tissue. Glucose uptake and blood flow in adipose tissue exhibit insulin resistance in obesity, but because of the larger fat mass, adipose tissue does not seem to contribute substantially to the reduced insulin stimulated whole-body glucose uptake in obesity.