AJP - Regulatory, Integrative and Comparative Physiology, Vol 269, Issue 1 226-R228, Copyright © 1995 by American Physiological Society
Cellular oxygen consumption depends on body mass
R. K. Porter and M. D. Brand
Department of Biochemistry, University of Cambridge, United Kingdom.
Hepatocytes were isolated from nine species of mammal of different body
mass (and standard metabolic rate). The cells were incubated under
identical conditions and oxygen consumption measured. The rate of oxygen
consumption (per unit mass of cells) scaled with body mass with exponent
-0.18. In general, there was a 5.5-fold decrease in oxygen consumption rate
with a 12,500-fold increase in body mass. The decrease in oxygen
consumption rate was not due to an increase in cell volume with increasing
body mass but to a decrease in intrinsic metabolic activity of the cells.
This novel finding confirms and explains the decrease in oxygen consumption
rate measured in tissue slices from larger mammals by H. A. Krebs (Biochim.
Biophys. Acta 4: 249-269, 1950) and recently by P. Couture and A. J.
Hulbert [Am. J. Physiol. 268 (Regulatory Integrative Comp. Physiol. 37):
R641-R650, 1995].
