[Tetrahydroblopterin. Metabolism and metabolic role of unconjugated pteridines (author's transl)].

During the past 5 years, increasing studies have been devoted to the metabolism of tetrahydrobiopterin, which is the natural cofactor of the hydroxylases of aromatic aminoacids. This review describes some aspects of its metabolism, its involvement in the biosynthesis of related neurotransmitters. If search of further roles of tetrahydrobiopterin in human metabolism should be made, recent data lead to a new approach of neonatal hyperphenylalaninemia classification and understanding.