Validity of plasma factor in schizophrenia as measured by tryptophan uptake.

The uptake of L-tryptophan by chicken erythrocytes is stimulated by the presence of human plasma; however, there is no difference between the stimulation caused by plasmas of normal, chronic hospitalized nonschizophrenic, or chronic hospitalized schizophrenic subjects. Human plasma in general contains a complement-dependent antibody which reacts with an antigen present in the membrane of chicken erythrocytes resulting in hemolysis. Hemolysis can be maintained at a constant level by certain concentrations of Ca++ ion, the addition of which resulted in a gradual increase in tryptophan uptake. The calcium effect is probably due to the fact that the metal acts as a cofactor or modifier of component(s) of plasma causing higher uptake. The data indicate that hemolysis is not determining uptake of tryptophan by chicken erythrocytes.