Observations on Serum B₁₂ and Folate Activity in Normal and Leukemic Rats

In normal rats serum B₁₂ activity was found to be similar to man but serum folate activity was a good deal higher, in the range of 129 mµg./ml. Total body radiation and administration of 3MCA did not significantly alter B₁₂ or folate activity. Osborne-Mendel rats maintained on a vitamin A-deficient diet were found to have markedly lowered serum B₁₂ activity; the folate levels were only slightly decreased.

Studies on leukemic rats showed that eight animals with myelogenous leukemia had no elevation of the serum B₁₂ activity, and in these animals folate levels were slightly reduced. In two rats with radiation-induced acute lymphatic leukemia, serum B₁₂ activity was significantly elevated due to hepatic necrosis, and folate values were somewhat below normal levels.