Effect of N-acetylcysteine infusion on exercise-induced modulation of insulin sensitivity and signaling pathways in human skeletal muscle.

Autor:	Trewin AJ; College of Sport and Exercise Science and Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia;, Lundell LS; Departments of Physiology and Pharmacology and., Perry BD; College of Sport and Exercise Science and Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia;, Patil KV; Departments of Physiology and Pharmacology and., Chibalin AV; Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; and., Levinger I; College of Sport and Exercise Science and Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia;, McQuade LR; Australian Proteome Analysis Facility, Macquarie University, Sydney, New South Wales, Australia., Stepto NK; College of Sport and Exercise Science and Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia; Nigel.Stepto@vu.edu.au.
Jazyk:	angličtina
Zdroj:	American journal of physiology. Endocrinology and metabolism [Am J Physiol Endocrinol Metab] 2015 Aug 15; Vol. 309 (4), pp. E388-97. Date of Electronic Publication: 2015 Jun 23.
DOI:	10.1152/ajpendo.00605.2014
Abstrakt:	-Reactive oxygen species (ROS) produced in skeletal muscle may play a role in potentiating the beneficial responses to exercise; however, the effects of exercise-induced ROS on insulin action and protein signaling in humans has not been fully elucidated. Seven healthy, recreationally active participants volunteered for this double-blind, randomized, repeated-measures crossover study. Exercise was undertaken with infusion of saline (CON) or the antioxidant N-acetylcysteine (NAC) to attenuate ROS. Participants performed two 1-h cycling exercise sessions 7-14 days apart, 55 min at 65% V̇o2peak plus 5 min at 85%V̇o2peak, followed 3 h later by a 2-h hyperinsulinemic euglycemic clamp (40 mIU·min(-1)·m(2)) to determine insulin sensitivity. Four muscle biopsies were taken on each trial day, at baseline before NAC infusion (BASE), after exercise (EX), after 3-h recovery (REC), and post-insulin clamp (PI). Exercise, ROS, and insulin action on protein phosphorylation were evaluated with immunoblotting. NAC tended to decrease postexercise markers of the ROS/protein carbonylation ratio by -13.5% (P = 0.08) and increase the GSH/GSSG ratio twofold vs. CON (P < 0.05). Insulin sensitivity was reduced (-5.9%, P < 0.05) by NAC compared with CON without decreased phosphorylation of Akt or AS160. Whereas p-mTOR was not significantly decreased by NAC after EX or REC, phosphorylation of the downstream protein synthesis target kinase p70S6K was blunted by 48% at PI with NAC compared with CON (P < 0.05). We conclude that NAC infusion attenuated muscle ROS and postexercise insulin sensitivity independent of Akt signaling. ROS also played a role in normal p70S6K phosphorylation in response to insulin stimulation in human skeletal muscle. (Copyright © 2015 the American Physiological Society.)
Databáze:	MEDLINE
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