Meeting Abstract

41.4  Tuesday, Jan. 5  Metabolomic evidence that increased basal metabolic rate is linked to elevated metabolism in skeletal muscle of mice selected for high maximal metabolic rate WONE, B*; DONOVAN, E/R; HAYES, J/P; University of Nevada, Reno; University of California, Riverside; University of Nevada, Reno woneb@unr.edu

At the interspecific level, basal metabolic rate (BMR) and maximal metabolic rate (MMR) are typically correlated but the functional basis for this has proven elusive. The main contributors to BMR are the liver and kidneys while the main contributors to MMR are active skeletal muscles. Consequently, one of the pivotal challenges in the physiology of aerobic metabolism is elucidating the functional connection between BMR and MMR. We used gas chromatography-mass spectrometry (i.e., a metabolomic approach) to examine metabolites in the liver and skeletal muscles in Mus musculus from generation 7 of an artificial selection experiment on aerobic metabolism. After 7 generations of directional selection for increased mass-independent MMR, high MMR mice showed a 10.2% increase in mass-independent MMR and a concomitant 2.8% increase in mass-independent BMR compared to control mice. There were no significant differences between high MMR and control mice in the metabolic profiles of the liver or plantaris muscle. For the gastrocnemius muscle of mice selected for high MMR, multivariate statistics highlighted increased concentrations of acetylglutamic acid, aspartic acid, &beta-alanine, glutamic acid, succinic acid, and threonine—consistent with elevated metabolism in the skeletal muscle. These findings suggest that increased BMR in the high MMR mice is linked to elevated metabolism in the skeletal muscles that are more active during locomotion. Supported by NSF IOS 0344994.