Protein Ingestion Induces Muscle Insulin Resistance Independent of Leucine-Mediated mTOR Activation.

ABSTRACT: Increased plasma branched-chain amino acid concentrations are associated with insulin resistance, and intravenous amino acid infusion blunts insulin-mediated glucose disposal. We tested the hypothesis that protein ingestion impairs insulin-mediated glucose disposal by leucine-mediated mTOR signaling, which can inhibit AKT. We measured glucose disposal and muscle p-mTOR(Ser2448), p-AKT(Ser473), and p-AKT(Thr308) in 22 women during a hyperinsulinemic-euglycemic clamp procedure with and without concomitant ingestion of whey protein (0.6 g/kg fat-free mass; n = 11) or leucine that matched the amount given with whey protein (n = 11). Both whey protein and leucine ingestion raised plasma leucine concentration by approximately twofold and muscle p-mTOR(Ser2448) by ∼30% above the values observed i

SUBMITTER: Smith GI 

PROVIDER: S-EPMC4407849 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature