Development of ischemia-induced damage in defined mitochondrial subpopulations

Two mitochondrial subpopulations were isolated from guinea-pig heart by density gradient centrifugation. Under control conditions, both contain functionally intact mitochondria in which ischemic damage develops similarly. However, in one subpopulation adenine nucleotide content, adenine nucleotide translocase activity, oxidative phosphorylation and Ca 2+ uptake are a quarter lower than in the other one when related to mitochondrial protein mass. Cytochrome contents and uncoupled electron flux are the same. Changes develop most evidently at the very beginning of ischemia for NAD-linked respiration. When ischemia progresses, cytochromes and the translocator protein are gradually lost or inactivated. Thereupon only partial recovery of mitochondrial function can be obtained after 20 min of reperfusion.