PHENYLALANINE-HYDROXYLASE PARTICIPATION IN THE SYNTHESIS OF SEROTONINAND PTERIDINES IN DROSOPHILA-MELANOGASTER

Phenylalanine hydroxylase is involved in the synthesis of serotonin an d pteridines, probably catalysing the hydroxylation of tryptophan and a tetrahydropterin oxidase reaction, respectively. Supplementation of the wild-type Drosophila diet with either L-Phe or L-Trp induced a sig nificant increase in the phenylalanine hydroxylase concentration, whil e L-Tyr supplementation had no effect. The level of serotonin in adult heads of the PAH-defective mutant Henna recessive-3 was significantly lower than that obtained for the wild-type strain. A dr-fold increase in the concentration of phenylalanine hydroxylase is observed during the pharate adult head development. It occurs in parallel with the syn thesis of red pigments in the eye. (C) 1997 Elsevier Science Inc.