Lipid changes in mitochondria isolated from rat kidney after various periods of 
ischemia were analysed by thin-layer chromatography and gas-liquid 
chromatography. Free fatty acids were increased at 30 min and more so 
thereafter. Total phospholipid fatty acids decreased steadily. The proportion of 
diphosphatidylglycerol (cardiolipin) in the total phospholipid fraction 
decreased at 30 min, but the proportion of phosphatidylcholine and 
phosphatidylethanolamine in the total phospholipid fraction did not change until 
the irreversible phase of ischemic injury. We have shown that decrease of 
cardiolipin in mitochondrial membrane occurs early during ischemia, and only 
during the irreversible phase of ischemia are phosphatidylethanolamine and 
phosphatidylcholine broken down. It is postulated that these phenomena are due 
to activation of phospholipase in the mitochondrial membrane.