Studies on experimentally induced hyperphenylalaninemia.

The administration of several compounds that can increase plasma phenylalanine levels and/or inhibit phenylalanine hydroxylase in rats was studied in order to determine their usefulness in inducing a phenylketonuria-like state. The results of this investigation revealed that 4.5 microns/10 g p-chlorophenylalanine is more effective than L-phenylalanine, alpha-methylphenylalanine, trimethoprim, Bactrim and Septra, since the former compound produced both adequate hyperphenylalaninemia and marked inhibition of hepatic phenylalanine hydroxylase activity. In addition, a 24-h study provided important insights into the changing diurnal patterns of specified biochemical parameters.