Changes in Glucose Transporters, Gluconeogenesis, and Circadian Clock after Duodenal-Jejunal Bypass Surgery

Abstract

Bariatric surgery improves obesity and ameliorates glucose tolerance. This study was conducted to evaluate circadian clocks, gluconeogenesis, and glucose transport changes in hepatic and intestinal tissues after duodenal-jejunal bypass (DJB) surgery in a rat model. Twenty-five rats were randomly assigned to either sham group (10 rats) or DJB group (15 rats). Food intake, body weight, blood glucose, and serum insulin levels were measured. Quantitative RT-PCR, immunoblot, and immunohistochemistry were used to analyze genes and proteins in the liver and intestine. Food intake and body weight were not different between sham and DJB groups. Blood glucose level was significantly lower in the DJB group compared with that in the sham group. Although not significant, serum insulin level showed an increased tendency in DJB group. DJB induced marked expressions of glucose transporter-2 (GLUT2) in the liver and GLUT2 and sodium-dependent glucose transporter-1 (SGLT1) in the intestine. Gluconeogenic enzymes [phosphoenolpyruvate carboxykinase-1 (Pck1) and glucose-6-phosphatase (G6Pase)] decreased in the liver and increased in the intestine of the DJB group. Circadian transcription factor cryptochrome-1 (Cry1) increased in the liver and decreased in the intestine of the DJB group. Another circadian transcription factor period-2 (Per2) also increased in the liver and decreased in the intestine of the DJB group. In conclusion, this study suggests the possibility that Cry1 and Per2 may mediate decreased gluconeogenesis in the liver and increased gluconeogenesis in the intestine of the DJB group.