Absence of metabolic rate allometry in an ex vivo model of mammalian skeletal muscle

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• 作者：Ellen L. Robb ; Lucas A. Maddalena ; Valerie A. Dunlop ; Tamara Foster ; Jeffrey A. Stuart ; ^{jstuart@brocku.ca}
• 关键词：Allometry ; Scaling ; Metabolic rate ; Cell culture ; Myoblast ; Myotubes ; Skeletal muscle ; Liver ; Heart ; Brain
• 刊名：Comparative Biochemistry and Physiology - Part A ; Molecular & Integrative Physiology
• 出版年：2012
• 期刊代码：23_10956433
• 类别：abs
• 出版时间：July, 2012
• 卷：162
• 期：3
• 页码：157-162
• 文件大小：405 K

摘要

Within mammalian species, standard metabolic rate (SMR) increases disproportionately with body mass (M_b), such that the mass-specific SMR correlates negatively with M_b. This phenomenon can be explained in part by reduced cellular metabolic rates in larger species. To better understand the cause(s) of this cellular metabolic rate allometry we have used an ex vivo approach to isolate and identify potential contributors. Skeletal myoblasts from mammalian species ranging in M_b from 30 g to over 300,000 g were isolated and differentiated into myotubes in vitro. Oxygen consumption rates, citrate synthase (CS) activity, and lactate dehydrogenase (LDH) activity were measured in myotubes under standardized conditions. No correlation of any of these parameters was observed with species M_b, suggesting that there is no genetic contribution to between-species differences in cellular metabolic rates. Myotubes were incubated in serum from species ranging from 30 g to 400,000 g to determine whether between-species differences in the levels of metabolically important hormones might produce allometric trends in the cultured cells. However, there was no observed effect of serum donor M_b on any of the metabolic characteristics measured. Thus, there is no evidence for a relationship between skeletal muscle oxidative metabolism and M_b in an ex vivo model.