Effect of bypassing the proximal gut on gut hormones involved with glycemic control and weight loss

Abstract

Background: The reported remission of type 2 diabetes in patients undergoing Roux-en-Y gastric bypass has brought the role of the gut in glucose metabolism into focus. Our objective was to explore the differential effects on glucose homeostasis after oral versus gastrostomy glucose loading in patients with Roux-en-Y gastric bypass at an academic health science center.

Methods: A comparative controlled investigation of oral versus gastrostomy glucose loading in 5 patients who had previously undergone gastric bypass and had a gastrostomy tube placed in the gastric remnant for feeding. A standard glucose load was administered either orally (day 1) or by the gastrostomy tube (day 2). The plasma levels of glucose, insulin, glucagon-like peptide 1 and peptide YY were measured before and after glucose loading.

Results: Exclusion of the proximal small bowel from glucose passage induced greater plasma insulin, glucagon-like peptide 1, and peptide YY responses compared with glucose loading by way of the gastrostomy tube (P <.05).

Conclusions: Exclusion of glucose passage through the proximal small bowel results in enhanced insulin and gut hormone responses in patients after gastric bypass. The gut plays a central role in glucose metabolism and represents a target for future antidiabetes therapies.