FUNCTIONAL AND MOLECULAR-CHANGES IN F(O)F(1) ATP-SYNTHASE OF CARDIAC-MUSCLE DURING AGING

We have studied the functional and molecular changes of mitochondrial F(o)F1 ATP synthase of cardiac muscle during aging. ATP hydrolase acti vity was lower in sonic submitochondrial particles prepared from heart s senescent rats (24 months) than in those prepared from hearts of adu lt rats (12 months). Oligomycin-sensitive proton conduction of cardiac submitochondrial particles was greater in senescent rats than in adul t rats. The beta subunit of F1, detected immunologically in submitocho ndrial particles, was less in senescent rats than in adult rats. Expos ure of cardiac submitochondrial particles from adult rats to free radi cals, generated by Co-60, resulted in inactivation of ATP hydrolase ac tivity and a decreased content of F1. The structural and functional al terations of mitochondrial F(o)F1 ATP synthase during aging may be exp ected to affect energy metabolism, and our results suggest that they c ould originate from the action of free radicals generated in the inner mitochondrial membrane,