AJP - Gastrointestinal and Liver Physiology, Vol 238, Issue 1 34-G39, Copyright © 1980 by American Physiological Society
Effects of sulfation patterns on intestinal transport of bile salt sulfate esters
E. H. De Witt and L. Lack
The absorption of 14C-labeled 3 alpha-, the 7 alpha- and the 3 alpha,7
alpha-sulfate esters of taurochenodeoxycholate by guinea pig small
intestine was studied using in vivo and in vitro preparations. In vivo
ileal perfusions showed that sulfation markedly decreased uptake by the
ileal bile salt transport system and that the position and number of the
sulfate radicals affected the degree of transport inhibition. The following
relationships were found: transport of taurochenodeoxycholate (TCDC)
greater than TCDC-3-sulfate greater than TCDC-7 sulfate greater than
TCDC-3,7-disulfate with a decrease of approximately 90% between each pair.
In vitro, jejunal perfusions demonstrated that sulfation also decreased
passive flux. By use of an everted gut sac technique, the ability of ileum
to move the sulfated bile salts against a concentration gradient was
measured. Under these conditions transport of TCDC-3-sulfate was minimal,
and that of the 7-sulfate and 3,7-disulfate was not observed. In view of
the reported increased levels of sulfated bile salts after total or partial
biliary tract obstruction, our results support the concept of sulfation as
an adaptive mechanism for enhancing fecal elimination of bile salts.
