[Influence of 2 different milk formulas on renal tubular function in full- and pre-term newborn infants]

74 neonates (39 premature and 35 full term) were fed during first week of life on two available formulas: one was adapted and the other a powdered sweetened half skimmed milk. Urinary osmolarity was higher in neonates fed half skimmed milk. The study of blood parameters of renal function showed an higher urea nitrogen and a lower base excess in neonate fed half skimmed milk and in particular in prematures. Renal tubular function studied by means of volume/minute (V/m') of the clearance of free water (CH2O), of the clearance of osmotically active substances (COsm), and of the maximum tubular reabsorption of water (TcH2O), showed an increased clearance of osmotically active substances in both premature and full term neonates fed half skimmed milk and tubular reabsorption of water (TCH2O) in prematures. Such parameters of renal tubular function seem to be sensible indices for evaluating renal solute load of diet.