Phenylalanine and Tyrosine Utilization in Normal and Phenylalanine-Deficient Young Mice

Publisher Website
Google Scholar
Abstract
Young mice were maintained on normal or phenylalanine-deficient diets in which tyrosine and other amino acids were adequately supplied. Meals of similar composition but containing uniformly labeled C14L-phenylalanine or C14L-tyrosine were fed, expired C14O2 was collected and measured for 30 minutes, and the animals were then killed. Tyrosine and phenylalanine (as phenylethylamine hydrochloride) were isolated from the liver proteins and their C14 contents were determined. Mice fed the phenylalanine-deficient diet converted less of the absorbed phenylalanine to liver protein tyrosine and less to CO2 than did the animals fed the diet containing enough phenylalanine for normal growth. Absorbed C14L-tyrosine was not converted to liver protein phenylalanine by either the normal or phenylalanine-deficient mouse.