LE MÉTABOLISME DE LAL-, DE LAD- ET DE LADL-PHÉNYLALANINE CHEZ LE RAT

Abstract

Rats were injected with L-, D-, or DL-phenylalanine-1-14C. There was a lag period in the excretion of14C in respiratory CO2when D- or DL-phenylalanine was used compared with L-phenylalanine, but over a 24-hour period, the same quantity of14CO2was obtained from the three groups of rats. There was less radioactive phenylalanine and radioactive tyrosine incorporated into tissue proteins of rats injected with D-phenylalanine-1-14C 2 hours after injection. These rats also excreted slightly more radioactivity in their urine over the 24-hour period because of an increased excretion of phenylalanine and phenylpyruvic acid. The total quantity of radioactivity excreted in urine never exceeded 5% of the injected dose. This shows that L-, D-, and DL-phenylalanine are used very efficiently by the rat.