Model phenylketonuria (PKU) in the albino rat: behaviroal, biochemical, and neuroanatomical effects

Model phenylketonuria was induced in albino rats by injecting (at 1-20 days of age) and feeding (at 21-80 days) L-phenylalanine and D-L-para-chloro-phenylalanine. Behavioral testing on an eight-item battery occurred twice: first, whil the animals were either receiving the excess phenylalanines or not (original); and second, following a 90-day drug-free recovery period (retention). Results indicated drug-dependent deficits in learning and activity on both original and retention tests. Serum phenylalanine, serum tryptophan, and liver phenylalanine hydroxylase activity levels were positively correlated with the behavioral deficit. Clumped dense material in some myelin sheaths and associated degeneration of axons were found in experimental subjects.