Regulation of Glucose Uptake and Enteroendocrine Function by the Intestinal Epithelial Insulin Receptor

Ussar, Siegfried, Max-Felix Haering, Shiho Fujisaka, Dominik Lutter, Kevin Lee, Ning Li, Georg Gerber, Lynn Bry, and C. Ronald Kahn. 2017. “Regulation of Glucose Uptake and Enteroendocrine Function by the Intestinal Epithelial Insulin Receptor”. Diabetes.

Abstract

Insulin and IGF-1 receptors (IR and IGF1R) are major regulators of metabolism and cell growth throughout the body, however, their roles in the intestine remain controversial. Here we show that genetic ablation of the IR or IGF1R in intestinal epithelial cells of mice does not impair intestinal growth or development or the composition of the gut microbiome. However, loss of IR alters intestinal epithelial gene expression, especially in pathways related to glucose uptake and metabolism. More importantly, loss of IR reduces intestinal glucose uptake. As a result, mice lacking the IR in intestinal epithelium retain normal glucose tolerance during aging as compared to controls, which show an age-dependent decline in glucose tolerance. Loss of the insulin receptor also results in a reduction of GIP expression from K-cells and decreased GIP release in vivo following glucose ingestion, but has no effect on GLP-1 expression or secretion. Thus, the IR in the intestinal epithelium plays important roles in intestinal gene expression, glucose uptake and GIP production, which may contribute to pathophysiological changes in diabetes, metabolic syndrome and other insulin resistant states.
Last updated on 03/08/2023