Abstract
The results of the 1st experiment, together with those of all experiments with rats, form a compelling body of evidence that no rat "PKU [phenylketonuric] preparation" yet devised adequately simulates the irreversible intellectual impairments seen in most late-detected PKU children. The results of the last 2 experiments indicate that the detrimental behavioral effects of chronic overloads of P [L-phenylalanine] are attenuated by melatonin and specifically related to some aspect of P overloading of the rat.