URINARY NITRITE EXCRETION IN PREMATURE-INFANTS - EFFECTS OF TRANSFUSION OR INDOMETHACIN

Urinary nitrite excretion, an index of L-arginine-dependent nitric oxi de formation, was quantified daily for two weeks, in very low-birth-we ight (< 1500 g) premature infants. A transient 52% reduction in nitrit e excretion was noted on the day of transfusions (54 +/- 10 versus 26 +/- 6 mumol/mmol creatinine, before and during transfusion, respective ly, n = 24, p < 0.02). Indomethacin administration in six infants was associated with a dramatic increase in nitrite excretion from a basal median value of 3 to 76 mumol/mmol creatinine (p < 0.05). Nitrite excr etion returned to baseline on day 3 after indomethacin administration. In two infants who received indomethacin and transfusions on the same day, the stimulatory effect on nitrite excretion by indomethacin over whelmed any depressive effect of transfusions. These results suggest t hat L-arginine utilization is influenced by common therapeutic strateg ies in these high-risk infants.