A note on saturable and inhibitory kinetics of p-aminohippurate renal transport in rabbits.

In order to establish quantitative expressions of inhibitory kinetics in renal tubular secretion of p-aminohippurate (PAH), bolus i.v. injection and constant i.v. infusion of PAH were loaded to rabbits. Time courses of plasma concentration and urinary excretion rate were analyzed using compartment model with saturable rate process. Effects of sulfamethizole (SMZ) constant infusion and bolus injection on PAH renal excretion were also examined. Multi-compartment model for concurrent disposition of PAH and SMZ is presented. Excretory processes are composed of non-saturable filtration, saturable secretion which is subject to mutual inhibition, and reabsorption.