The role of foregut exclusion in the deterioration of glucose and lipid metabolism induced by a high-fat diet.

AIM: The small intestine may be involved in the improvement of glucose and lipid metabolism after bariatric surgery; however, the role of the foregut in metabolic changes remains unclear. This study used normal rats fed a high-fat diet (HFD) after bariatric surgery to determine the role of the foregut in glucose and lipid metabolism.

METHODS: Duodenum-jejunum bypass (DJB), gastrojejunostomy (GJ) and sham-operations were performed on Sprague-Dawley (SD) rats. Oral glucose tolerance, insulin sensitivity, β-cell function, lipid profile, glucose-stimulated glucose-dependent insulinotropic polypeptide (GIP) levels and glucagon-like peptide-1 (GLP-1) levels were measured. The rats were observed for 24 weeks post-surgery.

RESULTS: Food intake and body weight were similar between the groups during the study period (P>0.05). The DJB group exhibited better glucose and lipid metabolism than the other groups (P<0.05). Compared with the GJ group, the DJB group demonstrated superior oral glucose tolerance, insulin sensitivity and lipid profiles (P<0.05); β-cell function in the two groups was similar (P>0.05). The GIP levels were decreased in the DJB group and increased in the GJ group (P<0.05), and the GLP-1 levels were increased in the DJB and GJ groups (P>0.05).

CONCLUSIONS: We found that foregut exclusion can prevent disordered glucose and lipid metabolism. Additionally, decreased GIP secretion was associated with improvements in glucose tolerance and insulin sensitivity, particularly related to lipid metabolism. Increased GLP-1 benefited β-cell function; however, it could not reverse the disordered glucose and lipid metabolism induced by a HFD.