title: Decline in respiratory control ratio of rat liver mitochondria in old age.
abstract: Rat liver mitochondria isolated from old animals (27-33 months) showed a clear decline in the state 3 rate of respiration (presence of ADP) compared with mitochondria from mature animals (3-12 months) when using either succinate or NAD+-linked substrates. The state 4 rate of respiration (absence of ADP), which is a sensitive indicator of damage to the inner mitochondrial membrane, remained unchanged. Consequently the respiratory control ratio (state 3/state 4) declined. A loss of reserve capacity to maintain the ADP:O ratio was also observed. These observations indicate a decline in energy production in old animals.
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism*; D000375:Aging; D000818:Animals; D004734:Energy Metabolism; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D008293:Malates / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism*; D010101:Oxygen Consumption; D051381:Rats; D013386:Succinates / Q000378:metabolism; D019802:Succinic Acid
chemical_list: D005971:Glutamates; D008293:Malates; D013386:Succinates; D018698:Glutamic Acid; D000244:Adenosine Diphosphate; C030298:malic acid; D019802:Succinic Acid