BIOCHEMICAL ASPECTS OF THE INHIBITION OF LIVER REGENERATION BY TRANSFUSION OF HEPATECTOMIZED RATS WITH BLOOD FROM NORMAL RATS

Recent studies in this Laboratory concerning the effect of massive transfusions on parenchymal cell division in partially hepatectomized rats with blood from normal rats have shown the presence of a humoral factor whichplays a role in the control of DNA synthesis in regenerating liver. The effect of such transfusions has been tested on the levels of different enzymes involved in the synthesis of liver nucleic acids. The activities of nuclear RNA polymerase, and TdR- and TMP-kinases are not significantly altered by the transfusion, whereas DNA polymerase is significantly decreased. Moreover, the microsomes, which play a role in the regulation of DNA polymerase action by inhibiting the enzyme activity, have an inhibitory capacity approaching near normal levels. Thus, the decreased DNA synthesis for regenerating liver in transfused animals may possibly be explained in the basis of decreased DNA polymerase activity mediated by the microsomes of the liver. (Author)