[Effect of para-chlorophenylalanine and 5-hydroxytryptophan on the tryptophan content of the blood serum and its ability to stimulate tryptophan capture by the cells].

Intraperitoneal injection of parachlorphenylalanine to guinea-pigs leads to an increase in the blood tryptophan content and a reduction of blood serum activity that determines tryptophan cell uptake. Administration of 5-hydroxytryptophan brings about opposing changes in the parameters indicated. The presence of a reverse correlation between variations of tryptophan content and blood serum activity responsible for tryptophan cell uptake, which occur under the effect of substances that change the rate of serotonin synthesis indicates that these factors belong to the united system controlling tryptophan metabolism.