Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)OBJECTIVETo investigate the effect of biliopancreatic diversion (BPD) surgery on -cell function in grade I and II obese patients with type 2 diabetes using oral and intravenous glucose loads.RESEARCH DESIGN AND METHODSSixty-eight women were divided into the following three groups: 19 lean-control (23.0 2.2 kg/m(2)) and 18 obese-control (35.0 4.8 kg/m(2)) subjects with normal glucose tolerance, and 31 obese patients with type 2 diabetes (36.3 +/- 3.7 kg/m(2)). Of the 31 diabetic women, 64% underwent BPD (n = 20, BMI: 36.5 +/- 3.7 kg/m(2)) and were reassessed 1 month after surgery. Oral glucose tolerance tests and hyperglycemic clamps were performed. Mathematical modeling was used to analyze basal and stimulated -cell function, insulin sensitivity (IS), hepatic extraction (HE) of insulin, and delay time of -cell response to a specific plasma glucose concentration.RESULTSAfter BPD, restoration of the basal disposition index (P < 0.001) and improvement of the stimulated disposition indices in oral and intravenous glucose stimulation of the -cell were observed (P < 0.05). In both dynamic tests, there were no changes in the delay time of -cell response. IS for oral glucose stimulation (ISoral) and intravenous clamp glucose stimulation (ISclamp) was completely normalized (P < 0.001). ISoral and ISclamp increased approximately 5.0-fold and 3.5-fold, respectively (P < 0.01). The HE of insulin increased in the basal (P < 0.05) and stimulated states (P < 0.01).CONCLUSIONS-Cell function, IS, and HE of insulin improved after BPD, which improved glycemic control.361241174124Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Ethicon Endo-Surgery GroupFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2008/09451-7, 2008/07312-0]