A method for isolating aortic mitochondria exhibiting high respiratory control

A method for isolating tightly coupled mitochondria from an intima-media strip of swine aorta has been devised. The most important differences from previous methods were the use of a special device for mincing the aorta into a fine gruel before the homogenization, the incubation of the homogenate with elastase before centrifugation, and the use of an electrolyte-based medium for homogenization and centrifugation of the tissue rather than sucrose. The method resulted in the recovery of enough mitochondria from a single aorta so that a number of determinations could be performed. The respiratory control ratios using succinate, glutamate, glutamatemalate, and pyruvate-malate were 4.3, 8.2, 8.8, and 9.2, respectively. β-OH butyrate functioned very poorly as an electron donor under the conditions used in this experiment. Judging from their functional characteristics after rather rigorous treatment during isolation, swine aortic mitochondria, like cardiac mitochondria, are relatively resistant to damage.