The utilization of trytophan and its metabolites for pyridine nucleotide synthesis in tumors and host liver.

Tryptophan injected in large quantities (500-1000 mg/kg) causes a statistically significant rise in the pyridine nucleotide content of livers from animals bearing Ehrlich ascites tumor but there is no corresponding rise in tumor nicotinamide adenine dinucleotide (NAD). Similarly, incorporation of isotope from ring-labeled tryptophan into the nicotinamide moiety of NAD occurs rapidly in host liver but very slowly in tumor. Radioactivity from tryptophan tended to accumulate in 3hydroxy anthranilic acid in tumor but less so in liver. Quinolinic acid-2,3,7,8-14C is rapidly incorporated into liver NAD, but it