Modification of pH of normal and malignant mouse tissue by hydralazine and glucose, with and without breathing of 5% CO2 and 95% air.
We investigated the effects of hydralazine and glucose on the pH of several normal tissues and on RIF-1 radiation induced fibrosarcomas of mice that were breathing either air or a mixture of 5% CO2 and 95% air. Our goal was to investigate techniques to maximize the pH differences between normal tissue and tumors. Hydralazine (10 mg/kg) had only minor effects on pH of tumors and muscle; it lowered liver and kidney pH. In animals additionally breathing the air-gas mixture, pH was further lowered in liver and kidney. Glucose (0.6 mg/kg) by itself caused a major reduction in pH of liver, kidney, and adipose tissue. Only minor effects were seen in tumors and muscle. Causing the animals to breathe the gas-air mixture 4 h after glucose injection partially reversed the glucose effect in all normal tissues but caused additional reductions in tumors, particularly in small (less than 0.7 cm3) lesions. Thus, this last combination led to maximum differential between the pH of normal tissue and of tumor.