Incretin Response to a Standard Test Meal in a Rat Model of Sleeve Gastrectomy with Diet-Induced Obesity

Currently, the most effective treatment for obesity is bariatric surgery. Gastroduodenal bypass surgery produces sustained weight loss and improves glycemic control and insulin sensitivity. Previous studies have shown that sleeve gastrectomy (SG) produces similar results and implicate changes in incretin hormone release in these effects. Male Sprague-Dawley rats were divided into four groups; lean control (lean), diet-induced obesity (DIO), DIO animals that had undergone SG (SG), and DIO animals that had undergone a sham operation (sham). After a 2-week recovery period, the incretin response to a standard test meal was measured. Blood sampling was performed in free-moving rats at various time points using chronic vascular access to the right jugular vein. There was a significant increase in the bodyweight of DIO animals fed a high-fat/high-sugar diet compared with the lean animals, which was reversed by SG. DIO caused an impairment of the GLP-1 response to a standard test meal, but not the GIP response. SG resulted in a dramatic increase in the GLP-1 response to a standard test meal but had no effect on the GIP response. A rapid rise in blood sugar was observed in the SG group following a standard test meal that was followed by reactive hypoglycemia. SG dramatically increases the GLP-1 response to a standard test meal but has no effect on GIP in a rat model of DIO.