title: In vitro analysis of postnatal maturation of tubular p-aminohippurate transport in rat kidney.
abstract: Factors responsible for the developmental pattern in renal tubular PAH transport were analysed. The apparent Michaelis constant for PAH uptake is the same in all ages, whereas the maximum steady-state PAH uptake as well as the PAH efflux are increasing with age. In consideration of the significant differences in PAH efflux, the age-related differences in maximum steady-state PAH uptake do not accurately reflect the postnatal maturation of the transport mechanism. Therefore, the actual PAH uptake was calculated in renal cortical slices from rats of different ages. The data were related to units of wet weight, protein, and DNA. In conclusion, for the increasing renal tubular PAH transport with age both a quantitative increase in functional transport sites as well as an enhancement in the turnover-rate of the transport mechanism seem to be responsible.
mesh_terms: D000375:Aging; D000618:Aminohippuric Acids / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001692:Biological Transport; D004247:DNA / Q000378:metabolism; D005260:Female; D007672:Kidney Cortex / Q000378:metabolism; D007684:Kidney Tubules / Q000254:growth & development / Q000378:metabolism*; D008297:Male; D011506:Proteins / Q000378:metabolism; D051381:Rats
chemical_list: D000618:Aminohippuric Acids; D011506:Proteins; D004247:DNA