Plasma tryptophan level in chronic renal failure.

Total (Trp), free (fTrp) and bound (bTrp) tryptophan concentrations were measured in the plasma of hemodialyzed (HD), peritoneally dialyzed (CAPD) and conservatively treated (ND) patients in chronic renal failure (CRF). 1) A marked decrease of Trp and bTrp was found in all three groups of patients. 2) fTrp concentration was unaltered in the HD and CAPD groups but decreased in the ND patients.