Factors Which Affect Plasma Lactic Dehydrogenase in Tumor-Bearing Mice. ∗

Summary

1. Administration of 2-amino-4-arsenosophenol hydrochloride to Eperythrozoon-infected mice bearing transplantable tumors resulted in a lowering of plasma LDH early in the course of tumor development. 2. Splenectomy of Eperythrozoon-infected mice resulted in a marked rise in plasma LDH. 3. One week or more after tumor implantation, plasma LDH was elevated in all mice, with or without the presence of demonstrable Eperythrozoon in the blood. 4. It is suggested that Eperythrozoon infection contributes to the early rise in plasma LDH in mice inoculated with transplantable tumors.