Abstract
Using a microcalorimetric method, we have measured the heat productin in states 3 and 4 respiration of a mitochondrial preparation from rat heart ventricel. Adenosine triphosphate production in state 3 respiration was also determined for the same preparation after heat production was measured. In Tris-buffered solution with pyruvate and malate used as substrates, the total heat productions in states 3 and 4 respiration for a 10-min reaction period were about 709 and 207 mJ/mg of mitochondrial protein, respectively.2, 4-Dinitrophenol, and uncoupler of mitochondrial oxidative phosphorylation, increased the heat production in both states 3 and 4 respiration. On the other hand, antimycin A1, and inhibitor of the electron transport system, decreased the heat production in both states.When ventricle mitochondrial dysfunction was induced by the in vivo administration of a high dose of isoproterenol, heat production was increased in state 4 respiration.These results indicate that the calorimetric method can be used to evaluate the mitochondrial function.
