Behavioral, neurological, and biochemical effects of early L-phenylalanine plus DL-para-chlorophenylalanine

Keonate rats were intubated dally from 0-29 days of age with 1-phenylalanlne plus dl-parachlorophenylalanlne in order to produce an animal model of phenylketonuria (PKU). On the 29th day of intubation, the PKU group had elevated plasma phenylalanine and tyrosine levels and reduced body and brain weights as compared to an agar control group. At 85 days of age the PKU animals made significantly fewer bar presses than the agar controls, with the largest difference occurring when the subjects were shifted from a CRF to a DRL-5" schedule of reinforcement. The rats were decapitated at 330 days of age and the PKU animals had significantly less DNA and wet brain weight than the agar controls in the cerebellum only. Early drug treatment of the PKU animals produced behavioral, biochemical, and neurological characteristics that resemble those of human PKU.