Increased Reliance on Carbohydrates for Aerobic Exercise in Highland Andean Leaf-Eared Mice, but Not in Highland Lima Leaf-Eared Mice

Metabolites

Marie-Pierre Schippers¹  Grant B. McClelland¹  Oswaldo Ramirez²  Margarita Arana² 

[1] Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada;Unidad Biología Integrativa, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima 15102, Peru;

关键词: altitude;    carbohydrates;    respirometry;    aerobic capacity;    fuel use;    muscle;   

DOI  :  10.3390/metabo11110750

来源: DOAJ

【 摘 要 】

Exercise is an important performance trait in mammals and variation in aerobic capacity and/or substrate allocation during submaximal exercise may be important for survival at high altitude. Comparisons between lowland and highland populations is a fruitful approach to understanding the mechanisms for altitude differences in exercise performance. However, it has only been applied in very few highland species. The leaf-eared mice (LEM, genus Phyllotis) of South America are a promising taxon to uncover the pervasiveness of hypoxia tolerance mechanisms. Here we use lowland and highland populations of Andean and Lima LEM (P. andium and P. limatus), acclimated to common laboratory conditions, to determine exercise-induced maximal oxygen consumption ($\dot{\mathrm{V}}$O₂max), and submaximal exercise metabolism. Lowland and highland populations of both species showed no difference in $\dot{\mathrm{V}}$O₂max running in either normoxia or hypoxia. When run at 75% of $\dot{\mathrm{V}}$O₂max, highland Andean LEM had a greater reliance on carbohydrate oxidation to power exercise. In contrast, highland Lima LEM showed no difference in exercise fuel use compared to their lowland counterparts. The higher carbohydrate oxidation seen in highland Andean LEM was not explained by maximal activities of glycolytic enzymes in the gastrocnemius muscle, which were equivalent to lowlanders. This result is consistent with data on highland deer mouse populations and suggests changes in metabolic regulation may explain altitude differences in exercise performance.

【 授权许可】

Unknown