Effect of exchange transfusion on labeling of nuclei with thymidine-3-H and on mitosis in hepatocytes of normal and regenerating rat liver.

Exchange transfusion of blood (75-80% replacement of blood of recipient animals) was used to study the effect of blood-borne influences on nuclear labeling with thymidine-3H and on occur rence of mitosis in hepatocytes of rat liver. Intact or shamhepatectomized rats and partially hepatectomized rats were: (a) not transfused, (6) transfused with blood from rats with intact livers, or (c) transfused with blood from rats with partly excised livers. Partially hepatectomized or sham-hepatectomized rats were transfused once or twice (consecutively) at intervals after operation. Nonhepatectomized rats were transfused at equivalent times before they were killed. Transfusion had the following effects on labeling of nuclei and on occurrence of mitosis in hepatocytes: (a) no change in rats with intact livers transfused with blood from donor rats with either intact or partly excised livers, (o) depression or delay in partially hepatectomized rats transfused with blood from donor rats with intact livers (delay prolonged by 2 consecutive trans fusions), and (c) a variable depression or delay in partiall}'