Respiratory metabolism in rat tissues after autolysis in situ

Abstract

Rat tissues were subjected to autolysis in situ by incubation of the decapitated carcass at 37 C. After variable periods, samples of liver, kidney, and brain were either frozen in liquid propane (–190 C) for measurement of ATP or homogenized in sucrose-EDTA medium for polarographic measurements. The rate of disappearance of ATP was in the order brain > liver > kidney, and the "stable" ATP concentration after 60-min autolysis was greatest in kidney and least in brain. After 90-min autolysis, the "basal" (nonstimulated) oxygen consumption of homogenates was either increased (liver) or unchanged (kidney, brain), and the ADP-stimulated oxygen consumption was depressed in all three tissues. Respiratory control (stimulation of oxygen uptake by ADP) was abolished in brain after 60-min autolysis and in liver and kidney after 90 min when the substrates were alpha-ketoglutarate or glutamate; some control was observed when succinate was the substrate. Oxidative phosphorylation (ADP:O ratio) was not affected by 60-min autolysis. It is concluded that autolysis of 60-min duration results in depression of the rate at which ATP can be synthesized without affecting the energetic efficiency of ATP formation.