[Protein supply of rats and transaminase and succinate dehydrogenase activity]

The influence of an isocaloric diet containing 13 and 20% of crude protein on the activities of GOT, GPT and succinic dehydrogenase in rat livers was determined and compared to the growth as well as to the body composition of the animals. The weights of the animals were significantly increased, feed efficiency and consumption of metabolizable energy per gram of body increase were much better with higher protein supply. It may be concluded that protein retention was better while fat retention was nearly unaffected. The activities of the liver enzymes increased with the protein content of the diet, especially GOT 1,8 times and succinic dehydrogenase 3 times as compared to the respective values of the lower protein group. It is discussed that the activity of succinic dehydrogenase represents a suitable criterion for the evaluation of a changed metabolism, especially when protein supply is marginal.