[Participation of the ATP/ADP antiporter and fatty acids in oxidative phosphorylation uncoupling in squirrel liver mitochondria during winter hibernation and awakening]

Abstract

The parameters of energy coupling of mitochondria isolated from the livers of hibernating and awakening gophers were studied. The ATP/ADP-antiporter inhibitor carboxyatractylate slowed down the respiration rate, increased delta psi and decreased the ionic conductivity of the inner mitochondrial membrane as measured by the rate of the delta psi decline after addition of cyanide (in the presence of oligomycin and EGTA). A similar effect was produced by BSA, carboxyatractylate being fairly ineffective in the presence of BSA. In hibernating gophers the maximal rate of the uncoupled respiration and the ionic conductivity of the inner mitochondrial membrane were markedly decreased as compared with awakening gophers. The data obtained suggest that in awakening animals fatty acids induce the uncoupling of oxidative phosphorylation by the ATP/ADP-antiporter, this process being simultaneous with the activation of the respiratory chain.