Plasma acylcarnitines during insulin stimulation in humans are reflective of age-related metabolic dysfunction.

Journal Article (Journal Article)

The purpose of this study was to determine if plasma acylcarnitine (AC) profiling is altered under hyperinsulinemic conditions as part of the aging process. Fifteen young, lean (19-29 years) and fifteen middle-to older-aged (57-82 years) individuals underwent a 2-hr euglycemic-hyperinsulinemic clamp. Plasma samples were obtained at baseline, 20 min, 50 min, and 120 min for analysis of AC species and amino acids. Skeletal muscle biopsies were performed after 60 min of insulin-stimulation for analysis of acetyl-CoA carboxylase (ACC) phosphorylation. Insulin infusion decreased the majority of plasma short-, medium-, and long-chain (SC, MC, and LC, respectively) AC. However, during the initial 50 min, a number of MC and LC AC species (C10, C10:1, C12:1, C14, C16, C16:1, C18) remained elevated in aged individuals compared to their younger counterparts indicating a lag in responsiveness. Additionally, the insulin-induced decline in skeletal muscle ACC phosphorylation was blunted in the aged compared to young individuals (-24% vs. -56%, P < 0.05). These data suggest that a desensitization to insulin during aging, possibly at the level of skeletal muscle ACC phosphorylation, results in a diminished ability to transition to glucose oxidation indicative of metabolic inflexibility.

Full Text

Duke Authors

Cited Authors

  • Consitt, LA; Koves, TR; Muoio, DM; Nakazawa, M; Newton, CA; Houmard, JA

Published Date

  • October 28, 2016

Published In

Volume / Issue

  • 479 / 4

Start / End Page

  • 868 - 874

PubMed ID

  • 27693789

Pubmed Central ID

  • PMC5067238

Electronic International Standard Serial Number (EISSN)

  • 1090-2104

Digital Object Identifier (DOI)

  • 10.1016/j.bbrc.2016.09.116


  • eng

Conference Location

  • United States