Insulin-stimulated glucose disposal is not increased in anorexia nervosa

Insulin-stimulated glucose disposal was investigated using the euglycemic hyperinsulinemic glucose clamp technique in six women with anorexia nervosa (27.3 +/- 4.9 yr old; weight, 38.8 +/- 6.6 kg) and compared to results obtained in six normal women (22.6 +/- 1.2 yr old; weight, 58 +/- 2.5 kg) and seven obese women (26.8 +/- 7.7 yr old; weight, 92.5 +/- 13.8 kg). The glucose clamp was performed for 2 h using the Biostator and a continuous insulin infusion of 100 mU kg-1 h-1. Plasma levels of insulin were determined at 30-min intervals. Plasma levels of glucagon, FFA, glycerol, 3-hydroxy-butyrate, and alanine were measured basally. Blood glucose levels were similar in normal subjects and anorectic patients; they were slightly but significantly higher in the obese patients. The indices of insulin sensitivity measured were the MCR of glucose and the ratio of glucose infused to insulin infused (G/I). They were very similar in anorectic subjects [MCR, 13.5 +/- 2.4 (+/- SEM) ml kg-1 min-1; G/I, 5.2 +/- 0.9 mg/mU) and normal subjects (MCR, 13.5 +/- 1.7 ml kg-1 min-1; G/I, 5.2 +/- 0.4 mg/mU), but were significantly reduced in obese patients (MCR, 5.1 +/- 0.8 ml kg-1 min-1; G/I, 2.6 +/- 0.3 mg/mU; P less than 0.0025). Differences in plasma insulin among the three groups were not statistically significant. Plasma alanine levels were higher in anorectic than in normal or obese subjects, suggesting defective gluconeogenesis. Thus, insulin-stimulated glucose disposal is normal in patients with anorexia nervosa, a finding that contrasts with the previously reported increase in erythrocyte insulin receptors in this disease.