Enhancing effect of 5 α-cyprinol sulfate on mucosal membrane permeability to sodium ampicillin in rats

Effect of 5 α-cyprinol sulfate, a bile alcohol sulfate specific to carp bile, on rectal membrane permeability to sodium ampicillin (AMP Na) was examined in rats. AMP Na is not easily absorbed through rat rectal membrane without aid. 5 α-Cyprinol sulfate significantly enhanced the rectal membrane permeability to AMP Na even at a low concentration (6.25 mM), though sodium taurocholate needed a higher concentration (25 mM). Co-administration of phosphatidylcholine significantly suppressed the enhancing action of both sodium taurocholate and 5 α-cyprinol sulfate. On the other hand, calcium ion did not suppress the action of 5 α-cyprinol sulfate, although it did clearly suppress the action of sodium taurocholate. In conclusion, 5 α-cyprinol sulfate was found to have a potent enhancing effect on mucosal membrane permeability to water-soluble compounds. The enhancing mechanism of 5 α-cyprinol sulfate appeared to be different from that of sodium taurocholate.