Influence of hypoxanthine, allopurinol and adenine on resistance of rats and hamsters to hypobaric hypoxia.

The survival time of rats and hamsters in lethal hypoxia was measured after a sublethal exposure and a normoxia break, at the beginning of which purines were administered intraperitoneally in the following dosages: 25 mg/kg hypoxanthine, 50 mg/kg allopurinol, 25 mg/kg adenine. In rats, administration of hypoxanthine decreased the survival time by 20%, administration of allopurinol increased it by 25%. Oxygen overpressure of 5 kPa between the two hypoxic doses resulted in larger differences after hypoxanthine and allopurinol application as compared to normoxia break. In hamsters, the effect of allopurinol, hypoxanthine and oxygen was similar, but smaller than that in rats. Adenine did not significantly affect the survival time of rats or hamsters. If hypoxia was applied only once, the purines had no effect on the survival time of rats or hamsters. No measurable XOD activity was observed in hamsters, whereas in adult rats, 99.46 +/- 13.85 nkat/l were found.