Analysis of the radiorespirometric pattern after administration of [U-14C] glucose to Ehrlich ascites tumor-bearing mice

Ehrlich ascites tumor-bearing mice were subjected to ¹⁴CO₂ radiorespirometric analysis after administration of [U-¹⁴C]glucose, and the results were compared with the levels of host liver glycolytic enzyme activities and the uptake of the radioactivity into the liver. After IP administration of [U-¹⁴C]glucose, there was a progressive decline in respiratory ¹⁴CO₂ after the transplantation of the Ehrlich ascites tumor cells. The peak time (PT) was about 10 min on day 1, but thereafter was increasingly delayed, and could not be determined on day 13. Peak height (PH) and yield value (YV) were both considerably decreased, and again the magnitudes of the changes increased with the time after transplantation of the tumor cells. Glycolytic enzyme activities in the host liver were at normal levels 13 days after transplantation of the tumor cells. The uptake of the radioactivity into the liver after IP administration of [U-¹⁴C]glucose began to decline from day 5 and was 50% the value in normal mice 13 days after transplantation of the tumor cells. These results indicate that the radiorespirometric patterns with [U-¹⁴C]glucose reflects hepatic biochemical changes rather well.