Effect of prolonged cold exposure on oxidative phosphorylation and adenosinetriphosphatase activity of rat liver tissue

Abstract

Liver homogenates from control and one month cold-exposed (5 ± 1°C) rats were assayed for the P/O ratios characteristic of succinate and ß-hydroxybutyrate oxidations and for the level of adenosinetriphosphatase activity. With both substrates a significant lowering of the P/O ratio was observed in the cold-exposed group. Measurements of adenosinetriphosphatase activity in water homogenates showed that calcium and magnesium had strong activating effects. Little difference was found between control and experimental preparations except where both ions were used simultaneously. Here, the tissue from the cold-exposed group exhibited a slightly lower activity than the controls.