PHOSPHATE-METABOLISM IN THE RED-CELL OF SICK PREMATURES

The effect of different amounts of phosphorus supplementation on phosp hate metabolism was studied in two groups of sick preterms (B and C) d uring the first week of life. Group B included prematures that started formula milk feeding from day 3 and group C neonates on total parente ral nutrition with phosphate supplementation for 7 days. Twelve health y preterm neonates on formula milk feeding from day 2 (group A) were u sed as controls. On the 7th day of life all phosphate parameters measu red in group C (plasma and red cell inorganic phosphate and erythrocyt e ATP and 2,3-diphosphoglycerate) were found significantly lower than in the controls (1.60 +/- 0.07; 0.60 +/- 0.08; 1.45 +/- 0.09 and 4.42 +/- 0.18 vs. 2.05 +/- 0.10; 0.94 +/- 0.11; 1.69 +/- 0.07 and 6.24 +/- 0.42 mmol/l, respectively). The renal tubular reabsorption of phosphat e was also lower in this group (86.8 +/- 3.2 vs. 97.3 +/- 1.0%). No si gnificant differences were observed between groups B and A. Higher pho sphorus intake that was better achieved through early milk feeding pre vented phosphate depletion and the decline of 2,3-diphosphoglycerate i n the erythrocytes even of sick neonates which in turn might help to i mprove tissue oxygenation. The amount of parenteral phosphate suppleme ntation that could have beneficial effects on red cell phosphate param eters needs further investigation.