A prospective study of urinary proteins in early infancy.
Urinary concentrations of protein, albumin, beta 2-microglobulin, alpha-amino nitrogen, and creatinine were determined in forty-one full-term infants on seven occasions up to six months of age. Except for beta 2-microglobulin the concentrations were highest on the first day, followed by a rapid decrease to a constant level within two weeks. Protein diminished approximately seven-fold, albumin twenty-fold, alpha-amino nitrogen three-fold and creatinine five-fold. By contrast, beta 2-microglobulin, a low molecular weight protein, first increased three-fold between day 1 and day 5, thereafter decreasing slowly 17-fold during the first three months of age. The data indicate that different kidney functions mature asynchronously.
D000367:Age Factors; D000419:Albuminuria; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007668:Kidney / Q000254:growth & development / Q000378:metabolism*; D008297:Male; D009584:Nitrogen / Q000652:urine; D011446:Prospective Studies; D011507:Proteinuria; D001613:beta 2-Microglobulin / Q000652:urine
D001613:beta 2-Microglobulin; D003404:Creatinine; D009584:Nitrogen