On the mechanism of increased renal tubular reabsorption of drugs in alloxan diabetic rabbits.

Abstract

A study was made on the mechanisms of increased renal tubular reabsorption of chlorpropamide, sulfadimethoxine and N4-acetylsulfadimethoxine in diabetic rabbits. Urinary acidification with NH4Cl increased the renal tubular reabsorption of the drugs. Reabsorption coefficients of undissociated and dissociated molecules of the drugs were calculated using data of renal clearance of the drugs in alloxan diabetic rabbits and in NH4Cl-treated rabbits. Excellent accordance of the reabsorption coefficients as well as apparent reabsorption ratios in diabetic rabbits with those in NH4Cl-treated rabbits was observed. Apparently, renal tubular reabsorption of drugs depended exclusively on the urinary pH in the renal tubules. Parameters of renal tubular reabsorption in vivo could be well expressed by the parameters of distribution between CHCl3-CCl4 (1:1 by vol) containing soy bean lecithin and buffer solution.