Abstract

Piperonyl butoxide has been shown to reduce accumulation of cephaloridine in rabbit renal cortex; however, the mechanism responsible for this effect remains unclear. Cephaloridine is a zwitterion and its accumulation in renal cortex has been suggested to be regulated by both organic anion and cation transport systems. Thus, it was of interest to determine the effect of piperonyl butoxide on renal transport of p-aminohippurate (PAH, an organic anion) and tetraethylammonium (TEA, an organic cation). Although pretreatment with piperonyl butoxide markedly inhibited renal cortical uptake of cephaloridine, the same treatment had less inhibitory effect on either PAH or TEA uptake. Efflux of PAH from preloaded renal cortical slices was enhanced by pretreatment with piperonyl butoxide; however, TEA efflux was unaffected. Thus, piperonyl butoxide appears to have effects on renal membrane functions which result in differential effects on PAH, TEA, and cephaloridine transport.