Transport of anionic drugs across the basolateral membrane of proximal S2 segments of the rabbit kidney. Inverse relationship between the affinity to the p-aminohippurate transport system and the transport rate.

The renal p-aminohippurate (PAH) transport system, which resides in the S2 segments of proximal tubules, is a main tubular secretory system for drugs. Previous studies have shown that the hydrophobicity of drugs is positively correlated with their affinity for the basolateral PAH transporter. Affinity was deduced from inhibition of tubular 3H-PAH uptake.