[Modification of rat brain metabolism by long-term treatment with a peptide derivative].

Rats have been treated with a peptide derivative (Cerebrolysin) for 3, 5, 7 or 14 days. Investigations were made on cerebral protein and lactic acid concentration and on in vitro oxygen consumption of brain homogenates derived from treated rats. In all experiments treatment with the peptide derivative caused a significant decrease in cerebral lactic acid level and a gradual decrease in basal oxygen consumption of the brain homogenates correlated with duration of treatment. These effects could be observed after two different peptide derivative dosages, in differently aged animals and were always manifest and significant between the 3rd and the 7th day of treatment. The higher dosage of the peptide derivative (2.5 ml/kg body weight/d) caused a significant increase in maximal respiratory activity of brain homogenates after a further in vitro application of the derivative.