Mitochondrial longevity in vitro: the retention of respiratory control.

Isolated mitochondria were maintained metabolically active and coupled, i.e., capable of respiratory control, for several hours at 25 degrees C. An increase in respiratory control generally occurred during the first 4-8 hr of incubation followed thereafter by a decline. Longevity is a dynamic function as evidenced by its dependency on substrate and cofactors, thiamine pyrophosphate, in particular. Magnesium was also essential to longevity; coenzyme A, bovine serum albumin, and reducing agents were not. The findings are discussed in terms of cytoplasmic-mitochondrial interrelationships and mitochondrial autonomy.