Thermal inactivation and oxaloacetate inhibition of hepatic respiratory metabolism in male garden lizards of three different age-groups.

Thermal inactivation of hepatic succinic dehydrogenase (SH) (EC 1.3.99.1) at 51 +/- 1 degrees C resulted in a higher degree of inhibition in middle-aged and old than in young lizards. The oxaloacetate inhibition of SDH activity and that of oxygen uptake of liver homogenates after 1 h of incubation also showed a similar pattern of age dependency. With increase in time interval (from 15 to 60 min) the young and to some extent the middle-aged lizards showed a partial recovery from inhibition of oxygen consumption of liver homogenates, but not the old animals.