Uptake and acetylation of p-aminohippurate by slices of mouse kidney cortex

In slices of mouse kidney cortex, p-aminohippurate (PAH) is taken up by the organic anion transport system and then rapidly acetylated to p-acetylaminohippurate acid (PAAH), so that there is little net accumulation of PAH itself. The basic characteristics of this system have been described. Uptake may be measured as the total of PAH and PAAH combined. Both uptake and acetylation are dependent on aerobic metabolism. Succinate strongly inhibits net accumulation but has only a slight effect on the amount acetylated. This is attributed to the stimulation of efflux by succinate. In the mouse, the degree of acetylation as well as uptake varies with sex and strain, as well as with the drug used as substrate. When organic anion transport is employed as a test system for the assay of nephrotoxicity, it is proposed that slices from the mouse possess advantages over some other species in that acetylation and uptake provide dual endpoints.