Postnatal Development of Renal Hydrogen Ion Excretion Capacity in Relation to Age and Protein Intake

Svenningsen, N. W. and Lindquist, B. (Department of Paediatrics, University Hospital, Lund, Sweden). Postnatal development of renal hydrogen ion excretion capacity in relation to age and protein intake. Acta Paediatr Scand,63:721, 1974.—The cumulative and maximum renal hydrogen ion excretion capacity after induced acidosis has been studied in six term and twenty preterm infants at 1–3 and 44 weeks of postnatal age corresponding to for preterm babies 34–36 and 37–39 and for term babies 41–43 and 44–46 weeks of gestational age. The maximum net hydrogen ion (H+NAE) excretion capacity is lower in preterm than in term infants at 1–3 weeks of postnatal life. However, when approaching full gestation there is a considerable increase of the H+NAE excretion capacity of pretem infants almost equal to that found in term infants at 1–3 weeks of age. High dietary protein intake lasting for in average two to three weeks in preterm infants does not change the maximum renal H+ excretion during induced acidosis, but significantly enhances the initial increment of excretion rate of titratable acid (H+TA) in comparison to preterm infants fed low protein diets. The findings of the present investigation suggest that the development of renal hydrogen ion excretion capacity in preterm infants during the first weeks of life is related primarily to gestational age. This development may, however, to a certain degree respond to increased excretory needs imposed by dietary load.