Early Changes in Postprandial Insulin Secretion, Not in Insulin Sensitivity, Characterize Juvenile Obesity

The development of hyperinsulinemia and insulin resistance, both common in adults with established obesity, was studied in 16 children, weighing 169 ± 8% ideal body weight who were 12.7 ± 0.4 years of age with obesity duration of 0.5–8.5 years and continuous weight gain in excess of normal, and compared with 11 age-matched normal children. Early in the evolution of obesity, insulin and C-peptide responses to a normal meal were increased by 76 and 80%. The first insulin peak was higher (613 ± 53 pmol/ml) than normal (413 ± 59 pmol/ml, P P P r = 0.73, P r = 0.59, P −2 · min −1 ) and the normal (21.7 ± 1.5 mmol.m −2 · min −1 ) children. Initially higher than normal in obese children, the maximal rate of glucose uptake decreased with both obesity duration ( r = −0.67, P r = −0.66, P r = −0.17, NS). Fasting plasma insulin level and maximal glucose uptake were inversely related ( r = −0.67, P