Tissue Taurine Depletion Alters Metabolic Response to Exercise and Reduces Running Capacity in Mice. (12th November 2014)

• Record Type: Journal Article
• Authors: Ito, Takashi; Yoshikawa, Natsumi; Schaffer, Stephen W.; Azuma, Junichi
• Other Names: Chiarla Carlo Academic Editor.
• Is Part Of: Journal of amino acids. Volume 2014(2014)
• Publication Date: 2014-11-12
• Subjects: Amino acids -- Periodicals; Amino Acids; Amino acids; Electronic journals; Periodical; Periodicals; 612.015756
• DOI: 10.1155/2014/964680
• Languages: English
• ISSNs: 2090-0404

Abstract

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 α 1 and α 2 subunits of AMPK. The level of PPAR α 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.