Renal handling of phosphate in very low birthweight (VLBW) infants (less than 1.3 kg): effects of calcium and sodium intake.
Five patient groups of VLBW infants with the same P-intake but varying Ca and Na intake were examined as to their urinary excretion of P and Na and on their renal clearance of P. The effect of increasing the Na intake from 1.5 to 3 mEq/kg/24 h on C(P) was also examined. In the control group of infants with an intake of 210 mg Ca and 80 mg P/kg/24 h, the C(P) was significantly correlated with postnatal, but not postconceptional age. A relatively low Ca intake of 100 mg/kg/24 h led to age-related values two to three times as high, whereas Ca supplementation to a total intake of 250 mg/kg/24 h decreased the C(P) significantly. A Ca intake of 175 mg/kg/24 h led to C(P) similar to those seen with one of 100 mg/kg/24 h. Changing the Na intake from 1,5 to 3 mEq/kg/24 h did not influence the C(P). There was no correlation between UP and UNa in any of the patient groups examined.
D000375:Aging; D002118:Calcium / Q000494:pharmacology*; D005243:Feces / Q000032:analysis; D006801:Humans; D007223:Infant; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007668:Kidney / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology*
D010710:Phosphates; D012964:Sodium; D002118:Calcium