SPECIES-DIFFERENCES IN HEPATIC BILE-ACID UPTAKE - COMPARATIVE-EVALUATION OF TAUROCHOLATE AND TAUROURSODEOXYCHOLATE EXTRACTION IN RAT AND RABBIT

Dose-response curves for taurocholate and tauroursodeoxycholate were p erformed in rat and rabbit livers to get more insight into species dif ferences in the hepatic bile acid uptake. The bile acids showed satura tion kinetics in both animals, the V-max in rat being higher than in r abbit and the K-m being lower in the rat than in the rabbit for both t he bile acids, with no significant difference in the hepatic cells mor phometric parameters. Therefore, it is possible that differences in th e kinetic parameters are related to the number and, to a lesser extent , to the affinity of the transporters on the sinusoidal plasma membran es.