The influence of taurine on the bile acid maximum secretory rate in the guinea pig.
In view of the effect of taurine feeding on the cholestasis induced by sulfated lithocholate in the guinea pig, it was of interest to explore the influence of taurine on the bile acid secretory maximum (SRm) of chenodeoxycholic acid and of its glycine and taurine conjugates. Bile acid secretory rate measured in response to stepwise increasing rates showed for chenodeoxcholic acid an SRm of 147 +/- 6 nmol/min/g liver and any SRm that was higher (p less than 0.01) for taurine than for glycine (426 +/- 21 versus 327 +/- 24 nmol/min/g liver). Pretreatment for 3 days with taurine 0.5% in drinking water led to a 70% increase of the SRm for chenodeoxycholic acid. Analysis of the biliary bile acids after supplemental taurine demonstrated a large increment of tauroconjugates and no change in the percent of free bile acids or of sulfated forms. Experiments with labeled chenodeoxycholic acid showed no difference in the distribution of radioactivity between total liver, blood, bile, and urine on and off taurine thereby suggesting that neither sinusoidal uptake nor translocation across the cell were factors responsible for the difference in SRm. Inasmuch as taurine feeding increased the SRm for glycine by 30% and for taurine by 25%, it is suggested that taurine augments the canalicular excretion of bile acids that represents the rate-limiting step in the transfer of bile acids from blood into bile through a mechanism that cannot be explained only by a modification of the conjugation pattern.
Belli
D C
DC
Pediatric Gastroenterology Unit, Hôpital Ste-Justine, Montreal, Québec, Canada.
Fournier
L A
LA
Lepage
G
G
Yousef
I M
IM
Roy
C C
CC
D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism*; D002635:Chenodeoxycholic Acid / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology; D006168:Guinea Pigs; D007700:Kinetics; D008297:Male; D013654:Taurine / Q000494:pharmacology*
D001647:Bile Acids and Salts; D002635:Chenodeoxycholic Acid; D013654:Taurine; D005998:Glycine