Table of Contents
Journal of Amino Acids
Volume 2014 (2014), Article ID 964680, 10 pages
http://dx.doi.org/10.1155/2014/964680
Research Article

Tissue Taurine Depletion Alters Metabolic Response to Exercise and Reduces Running Capacity in Mice

1Department of Clinical Pharmacogenomics, School of Pharmacy, Hyogo University of Health Sciences, Kobe, Hyogo 650-8530, Japan
2Department of Pharmacology, University of South Alabama College of Medicine, Mobile, AL 36688, USA

Received 1 June 2014; Revised 20 October 2014; Accepted 20 October 2014; Published 12 November 2014

Academic Editor: Carlo Chiarla

Copyright © 2014 Takashi Ito et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Taurine is a sulfur-containing amino acid found in very high concentration in skeletal muscle. Taurine deficient mice engineered by knocking out the taurine transporter gene exhibit skeletal muscle wasting, structural defects, and exercise intolerance. In the present study, we investigated the mechanism underlying the development of metabolic abnormalities and exercise intolerance in muscle of the TauTKO phenotype. Running speed and endurance time of TauTKO mice were lower than those of control mice. Blood lactate level was elevated by >3-fold during treadmill running in TauTKO mice but remained largely unaltered by exercise in WT mice. Blood glucose was cleared faster during treadmill running in TauTKO mice than WT mice. AMP-activated kinase (AMPK) β-2 subunit was reduced in TauTKO muscle concomitant with a reduction in α1 and α2 subunits of AMPK. The level of PPARα and its targets, Gpx3, Cpt2, and Echs1, were also decreased in TauTKO muscle. Collectively, taurine depletion impairs metabolic adaptation to exercise in skeletal muscle, a phenomenon associated with a downregulation of AMPK and diminished NADH utilization by the mitochondrial respiratory chain. These findings suggest a crucial role of taurine in regulating energy metabolism in skeletal muscle of exercising TauTKO mice, changes that contribute to impaired exercise endurance.