Blunting of AICAR-induced human skeletal muscle glucose uptake in type 2 diabetes is dependent on age rather than diabetic status

John A. Babraj, Kristy Mustard, Calum Sutherland, Mhari C. Towler, Shaui Chen, Kenneth Smith, Kevin Green, Graham Leese, David Grahame Hardie, Michael J. Rennie, Daniel J. Cuthbertson

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

We demonstrated previously that, in healthy young men, 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside (AICAR) stimulates human muscle 2-deoxyglucose (2DG) uptake without detectable activation of muscle AMP-activated protein kinase (AMPK) but with extracellular-regulated kinase 1/2 (ERK1/2) activation. We tested whether AICAR stimulates muscle 2DG uptake in healthy older patients with or without type 2 diabetes (T2D). Six healthy young subjects (23 ± 3 yr, BMI 25 ± 2 kg/m−2; means ± SE), eight older subjects (59 ± 4 yr, BMI 28 ± 2 kg/m−2), and eight subjects with T2D (62 ± 4 yr, BMI 27 ± 2 kg/m−2) received a 6-h 2DG infusion (prime 10 mg/kg, 6 mg·kg−1·h−1) and AICAR (10 or 20 mg·kg−1·h−1) from 3 to 6 h. Quadriceps biopsies were taken at 0, 3, and 6 h. We determined 1) 2DG uptake, 2) total AMPKα activity, AMPK, acetyl-CoA carboxylase (ACC), and AS160 phosphorylation, and 3) ERK1/2 phosphorylation. Ten milligrams per kilogram per hour AICAR increased 2DG uptake by 2.9 ± 0.7-fold in young men (P < 0.001), 1.8 ± 0.2-fold in older men (P < 0.01), and 1.6 ± 0.1-fold in men with T2D; 20 mg·kg−1·h−1 AICAR increases were 2.5 ± 0.1-fold (older men, P < 0.001) and 2.2 ± 0.2-fold (men with T2D, P < 0.001). At 3-h AMPK activity and AMPK, ACC and AS160 phosphorylation were unchanged, but ERK1/2 phosphorylation increased at both AICAR doses. The fold changes of ERK1/2 phosphorylation and 2DG uptake closely correlated (R2 = 0.55, P = 0.003). AICAR stimulates muscle 2DG uptake in T2D to the same extent as in healthy age-matched controls, but there is an age-related reduction.
Original languageEnglish
Pages (from-to)E1042-E1048
Number of pages7
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume296
Issue number5
DOIs
Publication statusPublished - 22 Apr 2009

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