J. Scheibner et al., Indirect evidence that intestinal bile salt absorption in rats and hamsters is under positive feedback control, Z GASTROENT, 39(11), 2001, pp. 929
Bile salts are reabsorbed from the intestine by active and passive transpor
t mechanisms with great efficacy. Conflicting data do not allow to judge fo
r certainty whether bile salt absorption is under negative or positive feed
back control. To address this issue, we analyzed bile salt absorption in vi
vo along the entire intestinal tract of rats and hamsters that received int
raduodenal bile salt infusions for 54 h following interruption of the enter
ohepatic circulation. Taurocholate absorption in rats was complete, even wh
en un physiologically high concentrations of taurocholate were given. The c
ombined infusion of taurocholate together with potent inhibitors of bile sa
lt synthesis such as deoxycholate, taurodeoxycholate or taurochenodeoxychol
ate, failed to inhibit bile salt absorption. In the hamster, taurochenodeox
ycholate and taurocholate absorption was complete and could not be inhibite
d when given in supraphysiological concentrations. Finally, taurocholate ab
sorption was not impaired when deoxycholic acid was infused. These results
provide indirect evidence that bile salt absorption is under positive feedb
ack control regulated by luminal bile salt concentrations.