54. BILE SALTS (BS) EFFECTS ON SMALL INTESTINAL TRANSPORT

Scanty data are available on the effects of BS in the small intestine. Previous evidence, obtained only in in vivo systems, suggested an antiabsorptive effect on water and nutrient absorption, and an increase in tissue permeability. He studied the effects of Chenodeoxycholate (CDCA) and Ursodeoxycholate (UDCA) in the rabbit stripped small intestinal mucosa mounted in Ussing chambers, aiming at defining and characterizing such effects in an in vitro system. Results: 1. Both CDCA and UDCA (1mM) induced an increase in the rate of transmural Lactulose transfer in jejunum and ileum. 2. In the ileum such effect by CDCA was dose-dependent (being half maximal at 0.1mM). 3. The enhancement in Lactulose permeability by ImM CDCA was reversible, subsiding both in jejunum and ileum after BS removal. 4.Both BS, when added to the mucosal side of ileum, provoked a non additive, dose-dependent increase in short circuit current (Isc); on the contrary, no effect was seen in the jejunum. 5.CDCA 1mM added to the mucosal side of rabbit stripped ileal mucosa mounted in Ussing chambers, provoked an increase in net transephitelial Na absorption (probably due to the BS-Na cotransport) and a shift toward secretion in C1 transport. 6.Preliminary data show that lmM CDCA markedly inhibited the influx rates from 2mM Glucose, 2mM L-Phenylalanine and 5mM L-Glutamic acid.