AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 5 911-R917, Copyright © 1984 by American Physiological Society

ARTICLES

Oxygen consumption and oxidative capacity of muscles from young obese and nonobese Zucker rats

G. M. Wardlaw and M. L. Kaplan

The contribution of muscle tissue to the increased metabolic efficiency of the obese (fa/fa) Zucker rat at 6 wk of age was examined. In vitro O2 consumption was similar in obese and nonobese soleus and extensor digitorum longus (EDL) muscles, whether the animals were fed ad libitum, fasted, or treated with triiodothyronine. No phenotypic difference in the in vitro O2 consumption was seen when the muscles were preincubated with or without exogenous insulin. Pyruvate kinase, citrate synthase, succinate dehydrogenase, and cytochrome oxidase activities were similar in the soleus and the EDL muscles of both phenotypes. Phosphofructokinase and lactate dehydrogenase activities were higher in the soleus muscles from the obese rats, whereas hexokinase activities were higher in the EDL muscles from the nonobese rats. Mitochondrial and whole muscle homogenate respiration rates were similar in both phenotypes. The soleus and EDL muscles from the obese animals weighed less than those from the nonobese, but empty carcass weights were similar. Taken together these data suggest that muscle mass, muscle O2 consumption, and muscle oxidative capacity are similar in 6-wk-old obese and nonobese rats. Therefore other tissues are probably responsible for the increased metabolic efficiency of the young obese rat.

This article has been cited by other articles:

				X.-X. Han, A. Chabowski, N. N. Tandon, J. Calles-Escandon, J. F. C. Glatz, J. J. F. P. Luiken, and A. Bonen Metabolic challenges reveal impaired fatty acid metabolism and translocation of FAT/CD36 but not FABPpm in obese Zucker rat muscle Am J Physiol Endocrinol Metab, August 1, 2007; 293(2): E566 - E575. [Abstract] [Full Text] [PDF]