Biochemical Studies of Cytokinetic Changes during Tumor Growth

摘要: We have measured the cytokinetic changes which characterize growth of a hyperdiploid Ehrlich ascites tumor and investigated some possible underlying biochemical mechanisms. In this tumor, cell cycle increases from 9.5 hr on 2nd day to 39 14th proportion cells in S (thymidine index) declines 80 40% during same interval growth. Protein synthesis (measured by uptake leucine-14C 20-min pulse) at rate similar decline thymidine index, but there are no specific activity six enzymes: aryl sulfatase, β-glucuronidase, kinase, glucose-6-phosphate dehydrogenase, alkaline phosphatase, glutathione reductase. Transplantation 107 plateau-phase tumors (14 16 days) new hosts causes protein increase immediately. The other hand, remains constant for 5 6 after transplantation then doubles within next 4 hr. rise is prevented (or delayed) when animals breathe 6% oxygen. Hypoxia also decreases index 2-day tumors, it does not alter length cycle. results suggest that progressive accumulation G1 may reflect relative inefficiency anaerobic metabolism producing energy ( e.g. , ATP) necessary movement into phase.