Time course of changes in phospholipid in cardiac mitochondria from rats recovering from prolonged swimming.

The time course of the recovery of cardiac mitochondrial phospholipids was investigated in rats subjected to a 3 hour loaded swim. The 3 hour swim caused a 50% reduction in mitochondrial phospholipids compared with the level in sedentary controls. During the first 12 hours of the recovery period, phospholipids tended to increase but fell again before reaching control values by 120 hours after the swim ended. Phospholipid recovery in microsomes was completed in 12 hours. Total mRNA in cardiac tissue decreased by about 15% in rats subjected to a 3 hour loaded swim but recovered to control levels in the first 12 hours of the sedentary recovery period. Thus, fluctuations in cardiac mitochondrial phospholipids do not parallel the changes in total mRNA in cardiac tissue.