Maturation of p-aminohippuric acid transport in the developing rabbit kidney: interrelationships of the individual components.

The excretion of both endogenous organic (aryl) acids, such as benzoic acid, and exogenous ones, such as p-aminohippuric acid (PAH), penicillin, and furosemide, is reduced in the human neonate and other immature animals. The unique developmental pattern of aryl acid transport in immature rabbit kidney cortex slices is produced by the interrelationships of PAH uptake, efflux, and amount of intracellular binding protein, all of which reach mature levels at different ages.