Intravenous glucose tolerance test—Derived glucose effectiveness in bulimia nervosa

The aim of the present study was to estimate insulin secretion, insulin sensitivity (SI), and glucose effectiveness at basal insulin (SG) in subjects with bulimia nervosa. Eight bulimic patients and eight age-, body mass index—, and sex-matched healthy control subjects without a family history of diabetes were studied. The subjects all had normal glucose tolerance. They underwent a modified frequently sampled intravenous glucose tolerance test; glucose (300 mg/kg body weight) was administered, and insulin (4 mU/kg body weight/min) was infused from 20 to 25 minutes after administration of glucose. SI and SG were estimated by Bergman's minimal model method. Basal insulin (27 ± 3 v 45 ± 3 pmol/L) was significantly lower in bulimic patients than in normal controls ( P < .05), but basal glucose was similar between the two groups (4.5 ± 0.1 v 4.9 ± 0.1 mmol/L, P > .05). The glucose disappearance rate (KG) and acute insulin response to glucose estimated by the intravenous glucose tolerance test (AIR glucose) were similar between the two groups (KG, 1.35 ± 0.29 v 2.20 ± 0.21 min −1, P > .05; AIR glucose, 2,920 ± 547 v 2,368 ± 367 pmol/L · min, P > .05). No significant difference was observed in SI between the two groups (1.34 ± 0.18 v 1.25 ± 0.20 × 10 −4 · min −1 · pmol/L −1, P > .05). On the other hand, glucose effectiveness at basal (SG) and zero (GEZI) insulin was significantly diminished in comparison to normal controls (SG, 0.011 ± 0.002 v 0.024 ± 0.002 min −1, P < .01; GEZI, 0.008 ± 0.002 v 0.017 ± 0.003 min −1, P < .01). Thus, bulimic patients with normal glucose tolerance without a family history of diabetes were characterized by normal insulin secretion, normal SI, and reduced SG and GEZI.