Influence of leucine on protein metabolism, phosphokinase expression, and cell proliferation in human duodenum1,3.

Background: Although leucine increases protein anabolism through the mammalian target of rapamycin (mTOR) pathway in human muscles, its effects on intestinal mucosal proteins remain unknown.

Objective: We aimed to assess the effects of leucine on duodenal protein metabolism in healthy humans and to elucidate the signaling pathways involved.

Design: Eleven healthy volunteers received for 5 h, on 2 occasions and in random order, an enteral supply of maltodextrins (0.

Effects of essential amino acids or glutamine deprivation on intestinal permeability and protein synthesis in HCT-8 cells: involvement of GCN2 and mTOR pathways.

GCN2 and mTOR pathways are involved in the regulation of protein metabolism in response to amino acid availability in different tissues. However, regulation at intestinal level is poorly documented. The aim of the study was to evaluate the effects of a deprivation of essential amino acids (EAA) or glutamine (Gln) on these pathways in intestinal epithelial cells.