GLUCOSE-METABOLISM IN RIF-1 TUMORS AFTER REDUCTION IN BLOOD-FLOW - ANIN-VIVO C-13 AND P-31 NMR-STUDY

Low pH appears to enhance the effectiveness of therapeutic hyperthermi a. C-13 and P-31 NMR spectroscopy have been employed to examine the po ssibility that elevating glucose in a solid tumor while simultaneously reducing tumor blood flow would induce a more profound acidosis than either treatment alone. When blood flow in RIF-1 tumors was acutely re duced by administration of hydralazine and additional glucose was deli vered locally by intratumoral injection, tumor acidosis (as determined by P-31 NMR spectroscopy) during the period of reduced blood flow was not enhanced, relative to administration of hydralazine alone. Tumor NTP/P-1 ratios decreased significantly within 20 min of hydralazine ad ministration, whether or not glucose was injected, although NTPIP1 rat ios were slightly higher in tumors that received extra glucose. Tumor lactate concentrations were not significantly different in glucose-sup plemented tumors, despite glucose concentrations that were 4 to 5 time s higher. When the added glucose was labeled with C-13, no correlation was detected between the pH in an individual tumor and the intensity of the 3-[C-13]-lactate resonance in the same tumor.