Inhibition of the intestinal absorption of bile acids using cationic derivatives: mechanism and repercussions

Biochem Pharmacol. 2007 Feb 1;73(3):394-404. doi: 10.1016/j.bcp.2006.10.014. Epub 2006 Oct 20.

Abstract

To pharmacologically interrupt bile acid enterohepatic circulation, two compounds named BAPA-3 and BAPA-6, with a steroid structure and 1 or 2 positive charges, were obtained by conjugation of N-(3-aminopropyl)-1,3-propanediamine with one or two moieties of glycocholic acid (GC). Both BAPA-3 and BAPA-6 inhibited Na+-dependent taurocholate (TC) uptake by Xenopus laevis oocytes expressing rat Asbt, with Ki values of 28 and 16 microM, respectively. BAPA-3 reduced Vmax without affecting Km. In contrast, BAPA-6 increased Km, with no effect on Vmax. Uptake of [14C]-GC by the last 10 cm of the rat ileum, perfused in situ over 60 min, was inhibited to a similar extent by unlabeled GC, BAPA-3 and BAPA-6. However, the intestinal absorption of these compounds was lower (BAPA-6) or much lower (BAPA-3) than that of GC. When administered orally to mice, both compounds (BAPA-3>BAPA-6) reduced the bile acid pool size, which was accompanied by up-regulation of hepatic Cyp7a1 and Hmgcr and intestinal Ostalpha/Ostbeta. A tendency towards a decreased expression of hepatic Ntcp and an enhanced expression of intestinal Asbt was also observed. Serum biochemical parameters were not affected by treatment with these compounds, except for a moderate increase in serum triglyceride concentrations. In sum, our results suggest that these compounds, in particular BAPA-3, are potentially useful tools for inhibiting the intestinal absorption of bile acids in a non-competitive manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bile Acids and Salts / metabolism*
  • Ileum / metabolism
  • Intestinal Absorption / drug effects*
  • Male
  • Mice
  • Organic Anion Transporters, Sodium-Dependent / physiology
  • Rats
  • Rats, Wistar
  • Sterols / pharmacology*
  • Symporters / physiology
  • Xenopus laevis

Substances

  • BAPA-3
  • BAPA-6
  • Bile Acids and Salts
  • Organic Anion Transporters, Sodium-Dependent
  • Sterols
  • Symporters
  • sodium-bile acid cotransporter