Relationship between abdominal visceral fat and metabolic risk factors in obese adolescents

The distribution of body fat may play an important role in determining the risk of obesity-related morbidity in obese adults. In view of the alarming increase in adolescent obesity, this article addresses whether defects in insulin action and secretion and increased intra-abdominal fat that typify central obesity in adults are expressed early in the course of developing obesity. The euglycemic hyperinsulinemic clamp technique with stable isotopes was used to determine insulin effects on glucose and glycerol turnover in obese and lean adolescents. The hyperglycemic clamp was used to quantitate insulin secretion, while magnetic resonance imaging was used to directly assess abdominal subcutaneous and visceral fat. The results indicate that obese adolescent girls have the following characteristics: 1) insulin resistance with major defects in oxidative and nonoxidative glucose metabolism; 2) hyperinsulinemia in the fasting state and in response to intravenous glucose; and 3) impaired suppression of total body lipid oxidation and plasma FFA concentrations in response to insulin. Am. J. Hum. Biol. 11:259-266, 1999. Copyright 1999 Wiley-Liss, Inc.