Ileal interposition surgery improves glucose and lipid metabolism and delays diabetes onset in the UCD-T2DM rat.

Background & Aims Bariatric surgery has been shown to reverse type 2 diabetes; however, mechanisms by which this occurs remain undefined. Ileal interposition (IT) is a surgical model that isolates the effects of increasing delivery of unabsorbed nutrients to the lower gastrointestinal tract. In this study we investigated effects of IT surgery on glucose tolerance and diabetes onset in UCD-T2DM (University of California at Davis type 2 diabetes mellitus) rats, a polygenic obese animal model of type 2 diabetes. Methods IT or sham surgery was performed on 4-month-old male UCD-T2DM rats. All animals underwent oral glucose tolerance testing (OGTT). A subset was killed 2 months after surgery for tissue analyses. The remainder was followed until diabetes onset and underwent oral fat tolerance testing (OFTT). Results IT surgery delayed diabetes onset by 120 ± 49 days compared with sham surgery ( P P P 7–36 ) excursions ( P P P P P Conclusions IT surgery delays the onset of diabetes in UCD-T2DM rats which may be related to increased nutrient-stimulated secretion of GLP-1 7–36 and PYY and improvements of insulin sensitivity, β-cell function, and lipid metabolism.