DECLINE WITH AGE OF THE RESPIRATORY-CHAIN ACTIVITY IN HUMAN SKELETAL-MUSCLE

Mitochondrial respiratory systems have been screened in 63 othopaedic patients of age ranging between 17 and 91 years. The results show a st atistically significant definite decrease with ageing of mitochondrial respiratory activity with pyruvate plus malate, succinate and ascorba te plus TMPD. This pattern is associated with an equally significant d ecrease with age of the enzymatic activity of complex I, II and IV. No significant decrease with age is, on the contrary, observed in the mi tochondrial content of cytochromes a + a(3), and c + c(1). Preliminary Western blot analysis indicates an altered polypeptide pattern in cyt ochrome c oxidase. This study provides evidence for a decline with age of mitochondrial respiratory activity in human skeletal muscle, affec ting complex I, II and IV.