Hypoxanthine, xanthine, and uric acid concentrations in the cerebrospinal fluid, plasma, and urine of hypoxemic pigs.

The concentrations of hypoxanthine, xanthine, and uric acid in plasma and cerebrospinal fluid (CSF), as well as the urinary output of hypoxanthine and xanthine, were measured in four groups of pigs (three groups with different degrees of hypoxemia and one control group). During hypoxemia with arterial O2 tension between 2.1 and 3.0 kPa [group 1, fractional inspired oxygen (FiO2) = 0.08], hypoxanthine increased in CSF from a mean basal value of 18.1 to 39.3 mumol/L at death (p less than 0.02), in plasma from 25.4 to 103.6 mumol/L (p less than 0.05), and in urine from 21.3 to 87.1 nmol/kg/min (p less than 0.02). Xanthine changed in a similar way: in CSF from 4.0 to 10.6 mumol/L (p less than 0.02), in plasma from 0.7 to 48.1 mumol/L (p less than 0.02), and in urine from 4.0 to 12.6 nmol/kg/min (p less than 0.05). Uric acid increased in CSF from 2.7 to 11.6 mumol/L (p less than 0.05), and in plasma from 15.4 to 125.0 mumol/L (p less than 0.02). During hypoxemia with arterial O2 tension between 3.0 and 4.0 kPa (group 2, FiO2 = 0.11), hypoxanthine increased in the CSF from 14.7 to 42.9 mumol/L (p less than 0.02). Plasma hypoxanthine increased from 20.3 to a maximum of 44.1 mumol/L (p less than 0.02), but decreased to initial values by the time of death. The urinary excretion of hypoxanthine increased from 13 to 54 nmol/kg/min (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)