Oxyntomodulin stimulates intestinal glucose uptake in rats

Area of Science:

• Gastroenterology
• Endocrinology
• Molecular Biology

Background:

• Enteroglucagon peptides are implicated in intestinal adaptation, influencing mucosal growth and nutrient absorption.
• Oxyntomodulin, a bioactive enteroglucagon form, was investigated for its role in nutrient uptake.
• Glucagon's effects on intestinal adaptation were also examined for comparison.

Purpose of the Study:

• To test the hypothesis that oxyntomodulin infusions stimulate glucose and amino acid uptake.
• To compare the effects of oxyntomodulin with those of glucagon on intestinal adaptation.
• To elucidate the specific roles of these peptides in nutrient absorption.

Main Methods:

• Rats received intravenous infusions of saline, oxyntomodulin, or glucagon for 7 days.
• Plasma hormone levels were measured, and intestinal dimensions were assessed post-infusion.
• In vitro everted sleeve technique was used to measure brush border uptake of D-glucose and L-proline.

Main Results:

• Oxyntomodulin and glucagon significantly increased total intestinal glucose uptake capacity (44% and 53%, respectively).
• Oxyntomodulin demonstrated a potent effect on ileal glucose uptake (215%), while glucagon's effect was most pronounced in the jejunum (63%-85%).
• Neither peptide influenced food intake, body weight, intestinal dimensions, or proline uptake.

Conclusions:

• Oxyntomodulin acts as a specific stimulator of intestinal glucose uptake, contributing to intestinal adaptation.
• Glucagon's role as a regulator of intestinal glucose uptake is confirmed.
• These findings highlight distinct roles for enteroglucagon peptides in nutrient absorption.