Variations of lactate dehydrogenase in nude mice transplanted with human malignant tumors

Abstract

The LDH isozyme patterns of human tumors transplanted in nude mice exhibited the same mobility as that of human plasma and did not change with repeated transplantation. Some of the tumorous tissues also included mouse-originated patterns. The LDH activity of the plasma of tumorbearing mice varied among the tumors, but was neither correlated with the period of transplantation nor with the activity or weight of the tomorous tissue. However when human ovarian cancer cells were transplanted, plasma LDH activity increased rapidly shortly after transplantation. In contrast, with mice bearing human Grawitz's tumors no increase in plasma LDH activity was found even 18 weeks after transplantation; at the 14th week after transplantation however, the isozyme band of human tumor origin appeared. Therefore the degree of tumor tissue proliferation may affect LDH activity in the plasma of the transplant mouse.In these experiments, the LDH activity of several organs (the kidneys, muscles, spleen and liver) was found to either increase or decrease. It can thus be said that the changes in the isozyme patterns or activities of the plasmatic or organic LDH in mice bearing human tumors may be influenced by the specific characteristics of each transplanted tumor.