Does the hepatic branch of vagus mediate the secretion of glucagon-like peptide-1 during the Roux-en-Y gastric bypass surgery?

Objectives: The purpose of this study is to investigate the impact of the hepatic branch of the vagus and Roux-en-Y gastric bypass (RYGB) on the level of fasting and postprandial serum glucagon-like peptide-1 (GLP-1) in type 2 diabetic mellitus rats.

Methods: Randomized block design, factorial experiment. Forty-five type 2 diabetic rats were divided into four groups: sham operation (S, n = 10) and sham operation with the hepatic branch of the vagotomy (SV, n = 11), Roux-en-Y gastric bypass (RYGB, n = 12) and RYGB without preservation of the vagus (RYGBV, n = 12). Levels of fasting and postprandial serum GLP-1 30 min after 50 % glucose solution (2 g/kg) by gavage were determined before surgery and postoperatively at 1, 4, and 8 weeks. Interactions between RYGB and the common hepatic branch were also assessed.

Results: Roux-en-Y gastric bypass surgery significantly increased the concentration of postprandial serum GLP-1 and maintained it at a higher level (P < 0.05). Preservation of vagus hepatic branch only increased the concentration of postprandial serum GLP-1 at the initial stage (P < 0.05), which gradually weakened over time (P > 0.05). Both RYGB and vagotomy of the hepatic branch had no influence on fasting serum GLP-1 (P > 0.05).

Conclusions: During RYGB surgery for the long-term treatment of T2DM, preservation of the hepatic branch of the vagus might have no impact on serum GLP-1 level.