GLUCOSE EFFECTIVENESS, PERIPHERAL AND HEPATIC INSULIN SENSITIVITY, INOBESE AND LEAN PREPUBERTAL CHILDREN

OBJECTIVE: To determine whether prepubertal (Tanner I) obese children have diminished peripheral insulin sensitivity (IS) and to determine w hether obesity affects the ability of glucose to stimulate its own dis posal (glucose effectiveness, GE). DESIGN: Cross-sectional study of tw o groups. SUBJECTS: Seven obese (BMI > 75% for age, 26.1 +/- 2.1 kg/m( 2), age, 10.9 +/- 0.6 y, mean +/- SE) and six lean (BMI, 15.7 +/- 0.7 kg/m(2), age, 10.3 +/- 0.7) children. METHODS: IS and GE by 3 h freque ntly sampled intravenous glucose tolerance test with 13% [6-6] D-2-glu cose in the glucose bolus (250 mg/kg), hepatic glucose production usin g Steele's non steady state equations and hepatic insulin resistance ( HR) multiplying by the mean insulin level. RESULTS: IS was markedly lo wer (p < 0.01) in the obese group (0.27 +/- 0.08 (pmol l)/min) compare d to the lean group (2.23 +/- 1.0 (pmol/l)min) whereas GE was higher ( 0.021 +/- 0.001 vs 0.015 +/- 0.001/min, p < 0.05). HR was increased in the obese (132 +/- 28 vs 58 +/- 14 mg/kg/min/pmol/l, p < 0.05). Obese children also had increased insulin secretion over the first 19 min C o < 0.01) following glucose although plasma glucose levels were higher (p < 0.01). CONCLUSION: These results show that obese prepubertal chi ldren have peripheral and hepatic insulin resistance. The increases in GE and insulin secretion may be compensatory responses to these defec ts in insulin action.