Regulation of Energy Flow and Heat Production

MICHAEL N. BERRY, ANTHONY R. GRIVEU. and PATRICIA G. WALLACE 

The isolated liver cell preparation provides a useful tool for such studies. The characteristic feature of such preparations is the stimulation of 02-consumption by added substrate, even though measurement of adenine nucleotide or inorganic phosphate concentrations fails to detect any changes resulting from substrate addition. Moreover, the presence of an uncoupling agent which markedly lowers the phosphorylation state frequently fails to stimulate 02-consumption to the extent brought about by substrate addition alone, t 

MICHABL N. BBRRY, ANTHONY R. 6RIVBLL, and PATRICIA 6. WALLACB 

The processes which go to make up the basal metabolism are not well delineated. Nevertheless, it is known that the basal metabolic rate is reasonably constant for a given individual. Although affected by age, sex, diet, training, etc., the major influence appears to be body size. It has been established for many years that under similar conditions the basal metabolism of various mammals, as measured by the rate of heat loss in the basal state, is approximately proportional to the surface area, whereas heat loss is inversely related to body weight. In consequence, small mammals such as the shrew with a large surface to volume ratio have a basal metabolic rate some sixty times greater than man and perhaps two hundred times that of an elephant. 

In the electrochemical interpretation of metabolism presented here, we discount the significance of chemical reactions occurring under conditions well removed from equilibrium as important sources of heat production. Rather, we identify those processes associated with electronic and protonic current flow as the critical elements in heat production. The relationship between body surface area and heat production becomes more readily understandable when it is appreciated that these heat-producing processes take place within cellular membranes (or the microtrabecular lattice). Thus, the finding that heat production is a function of body surface area rather than tissue mass may be a macroscopic reflection of the fact that cellular electrochemical reactions occur in two dimensions, in contrast with three-dimensional, scalar chemical reactions. 

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