Renal excretion of bile acids: taurocholic, glycocholic, and cholic acids

Abstract

The renal clearance (in dogs) of taurocholate, after correction for plasma-protein binding, is less than the glomerular filtration rate. Clearance increases toward, but does not attain, the filtration rate as filtered load is increased. Clearance is not influenced by changes in urinary pH or flow, nor by administration of probenecid or benzmalecene (20–25 mg/kg). The site of reabsorption demonstrated in stop-flow studies is the proximal tubule. Tubular fluid-to-plasma ultrafiltrate ratios less than unity were observed. The results are interpreted as indicating active reabsorptive transport. Glycocholate and cholate are handled in a similar manner. Possible mechanisms of interaction of this reabsorptive system with the organic acid secretory system are considered.