1. The renal clearances of [14C]glycocholate, [14C]taurocholate and [3H]glycochenodeoxycholate-3-sulphate were determined in bile duct obstructed rats.
2. Comparisons of the bile acid clearances with glomerular filtration rates (GFR) indicate that most of the filtered bile acids are reabsorbed.
3. Inhibition studies with p-aminohippurate (PAH) and probenecid suggest that a proportion of the bile acids in urine is secreted.
4. Attempts were made to increase the renal clearance of the bile acids by the administration of pharmacological agents.
5. An infusion of sodium acetate (0.3 mol/l) increased the clearance of the radioactive bile acids and augmented the urinary excretion of endogenous 3α-hydroxy bile acids and reduced their concentration in plasma.