Urinary loss of oxypurines in hypoxic premature neonates.

The daily urinary excretion of the oxypurines hypoxanthine, xanthine and uric acid during each of the first 3 days of life was determined in premature infants without hypoxia (PI) and in hypoxic premature infants (HPI) with the respiratory distress syndrome. The loss of uric aic was statistically significantly greater in the HPI during days 1, 2, and 3 of life, and so was the loss of xanthine on days 1, and 2, but not on day 3. As to the loss of hypoxanthine, no difference could be shown. In both groups of infants the excretion of hypoxanthine and xanthine together made up about 2% of the total oxypurine loss for each day, the loss of xanthine being the greater of the two. The results did not seem to bear relation to differences between the two groups concerning urinary output, birth weight, gestational age, method of delivery, or administration of exogenic purines. So it appears that the increased loss of oxypurines in HPI is caused by the impact of hypoxia, probably owing to be compromised cellular respiration with a subsequent general displacement of the purine metabolism in the catabolic direction.