1426-P: Increased Insulin Secretion and Glucose Effectiveness Result in Improved Glucose Tolerance in Obese Subjects Two Months after Gastric Bypass and Sleeve

The early effects of bariatric surgery on insulin secretion and action in obese subjects with type 2 diabetes (T2D) remains poorly investigated. Here we assessed the mechanisms resulting in improved glucose intolerance using the oral minimal model approach. An oral glucose tolerance test was performed before and 2 months after bariatric surgery in 16 obese T2D subjects (9 bypass, 7 gastric sleeve) and in 8 healthy control subjects. For each visit, body mass index (BMI) was measured, and the oral glucose and the insulin and C-peptide minimal models were used to estimate insulin sensitivity (SI) , glucose effectiveness (GE) , total β-cell responsiveness (Φtot) , disposition index (DI) and total hepatic insulin extraction (HE) . Bariatric surgery resulted in a significant reduction (similar between bypass and sleeve groups) in BMI by 14% (from 42±5 to 36±4 kg/m2) . Glucose tolerance increased comparably after bypass and sleeve, but remained impaired compared to the control group (Figure 1) : GE, Φtot, DI and HE were equally increased following bariatric surgery, whereas insulin action (SI) remained unaltered in the two groups. These results suggest that improved glucose tolerance in obese T2D subjects 2 months after bariatric surgery is attributable mainly to an increase in insulin secretion and glucose effectiveness rather than an improvement in insulin action. Disclosure R. Visentin: Research Support; Becton, Dickinson and Company, MannKind Corporation, Sanofi-Aventis Deutschland GmbH. K. Brodersen: None. N. Moller: None. C. Dalla Man: Research Support; Becton, Dickinson and Company, Sanofi-Aventis Deutschland GmbH. M.F. Nielsen: None. Funding Novo Nordisk Foundation