[Enzymes of carbohydrate and lipid metabolism in dependence on age (author's transl)].

The levels of the rat liver enzymes glucose-6-phosphate-dehydrogenase, alpha-glycerophosphate-dehydrogenase and citrate cleavage enzyme decrease between the age groups of 3 and 18 months. The half-life time of these enzymes is uneffected by age and the diminished levels of the enzymes in the liver of old rats can be ascribed to a reduced rate of enzyme synthesis. The half-life time of malic enzyme decreases as a function of age and this increased enzyme destruction may contribute to the diminished malic enzyme level of old rat liver.