MATURATION OF RENAL FUNCTION IN CHILDHOOD: CLEARANCE STUDIES12

Abstract

Evidence has been presented by several investi- gators that functional capacity of the kidney in the premature and young infant is lower than in older children and adults. Schoenthal (1) using urea clearance, McCance and Young (2) urea and inu- lin clearances, Barnett (3) inulin clearance, and Gordon, Harrison and McNamara (4) urea clear- ance, showed that the infant had a lower glomeru- lar function when compared to the adult on the basis of a unit of surface area. Recently West et al. ( This present study was begun in 1945 to deter- mine the rate of maturation of certain of the kid- ney functions from the newborn period through childhood. The following functions were esti- mated: glomerular filtration rate, maximal tubular excretory capacity for para-amino-hippurate, urea clearance, and effective renal plasma flow.3 Sixty-three normal well children between the ages of two days and 12 years were studied. METHODS G.F. was determined as mannitol clearance by the single injection technique. A 20 minute period was allowed for 1 Presented before the Society for Pediatric Research,