Oxidative Metabolism in Cells Isolated from Brown Adipose Tissue

Abstract

Non‐stimulated brown fat cells exhibit a respiration controlled by availability of phosphate acceptor systems. Cells stimulated by nor‐epinephrine gradually lose the respiratory control as demonstrated by a diminishing response to carbonyl cyanide p ‐trifluoromethoxyphenylhydrazone (FCCP). The initial phase of increased respiration upon norepinephrine addition is characterized by an increased availability of activated fatty acids. A mechanism cannot be envisaged which could utilize all the ATP which would be produced by a tightly coupled oxidative phosphorylation system. A fine metabolic control must exist which regulates a balance between ATP production for fatty acid activation and a loosening of coupling between electron transport and phosphorylation.