Comparison of renal tubular transport of urate and PAH in water snakes: Evidence for differences in mechanisms and sites of transport

1. 1. Relationship between renal tubular transport of urate and p-aminohippurate (PAH) in water snakes of genus Natrix was studied in vivo and in vitro. 2. 2. PAH did not inhibit endogenous urate secretion in vivo. PAH did not inhibit uptake of urate, and urate did not inhibit uptake of PAH by kidney slices in vitro. Probenecid inhibited tubular secretion of urate and PAH in vivo and their uptake by kidney slices in vitro, but inhibition of urate transport was more marked than that of PAH transport. These data suggest that transport mechanisms for these two organic acids may differ. 3. 3. Ligation of renal portal vein had little effect on tubular urate secretion but tended to eliminate net tubular PAH secretion, suggesting that tubular transport sites for these two organic acids may differ.