DNA synthesis, blood flow, and glucose utilization in experimental rat brain tumors

The relationships between distribution of deoxyribonucleic acid (DNA)-synthesizing cells (S-phase cells) and blood flow and glucose utilization were investigated in rat brain tumors using an autoradiographic technique and immunoperoxidase staining for bromodeoxyuridine (BUdR). Two strains of rat brain tumor were used: strain A and B, both induced by the Rous sarcoma virus. Strain A was biologically more malignant than strain B. The blood flow was unevenly distributed in the tumor, compared with the contralateral cortex, the average blood flow in the tumor was about 50% in strain A and 60% in strain B. The distribution of blood flow did not correlate with the distribution of S-phase cells or with the distribution of vessels in the tumor in either strain A or B. The average glucose utilization in strain A was about 250% and in strain B about 170% of that of the contralateral cortex. The high glucose utilization area correlated well with the distribution of BUdR-positive nuclei in strain B. These findings suggest that the biological malignancy of a tumor correlates with glucose utilization rather than with blood flow, and that malignant brain tumors show a marked increase in glucose utilization for nucleic acid synthesis.