The peptide-based thrombin inhibitor CRC 220 is a new substrate of the basolateral rat liver organic anion-transporting polypeptide

Abstract

The peptidomimetic thrombin inhibitor CRC 220, 4-methoxy-2,3,6-trimethylphenylsulfonyl-L-aspartyl-D-4-amidinop henylalanyl- piperidide, is taken up into isolated rat hepatocytes through active, carrier-mediated transport. This uptake is inhibited by bile acids. Functional expression in Xenopus laevis oocytes was performed to identify the transport system responsible for the hepatocellular CRC 220 uptake. Injection of poly(A)+RNA in X. laevis oocytes resulted in a two- to three-times higher uptake of CRC 220, compared with uninjected or water-injected control oocytes. Taurocholate (200 mumol/L) inhibited this uptake completely. No uptake of the peptidomimetic thrombin inhibitor was observed, when X. laevis oocytes were injected with complementary RNA (cRNA) encoding either the cloned rat liver Na(+)-dependent taurocholate transporter Ntcp, the renal oligopeptide carrier rhaPT or the intestinal oligopeptide transporter PepT1. However, after injection of cRNA of the cloned rat liver Na(+)-independent organic anion transporting polypeptide oatp, a specific and saturable CRC 220 uptake was observed (Michaelis-Menten constant 29.5 mumol/L). Cis-inhibition with known oatp-substrates, e.g., 20 mumol/L Bromsulphalein (BSP), 2007 mumol/L taurocholate and 2007 mumol/L cholate, occurred in oatp-expressing X. laevis oocytes, whereas substrates of the two peptide carriers as well as dipeptide- and single-amino acid constituents of the thrombin inhibitor itself lacked any significant inhibitory effects. These data show that the modified dipeptide CRC 220 is a highly selective substrate of the organic anion transporting polypeptide oatp in the basolateral plasma membrane of rat hepatocytes.

Rifamycin SV and rifampicin exhibit differential inhibition of the hepatic rat organic anion transporting polypeptides, Oatp1 and Oatp2

“…3 Rapid hepatic Oatp1-mediated uptake has been already previously suggested to limit the oral bioavialability of the thrombin inhibitor, CRC 220. 32 In conclusion, this study demonstrates that rifamycin SV and rifampicin exhibit differential inhibition of the hepatic organic anion transporting polypeptides, Oatp1 and Oatp2, and that rifampicin is a selective inhibitor of Oatp2. Although additional studies with more recently cloned members of the Oatp family (e.g., liver-specific transporter, Lst-1 33 ) must be performed, the data suggest that rifamycin SV and rifampicin could be used to determine the in vivo relevance of Oatp1 and Oatp2 for the bioavailability and disposition of amphipatic xenobiotic compounds undergoing efficient hepatic elimination and excretion into bile.…”

Interactions of rifamycin SV and rifampicin with organic anion uptake systems of human liver

“…Coadministration of an OATP inhibitor could be used to increase the oral bioavailability of drugs with excessive OATP-mediated hepatic first-pass elimination such as, for example, the thrombin inhibitor CRC 220. 32 On the other hand, a coadministration of an OATP inhibitor could reduce the liver uptake of intrahepatically active drugs such as pravastatin 8,13 and, thus, lead to a decrease of drug efficacy and possible therapeutic failure. Furthermore, the development of specific inhibitors for individual Oatps/OATPs could help to explore the relevance of selective Oatps/OATPs for pharmacokinetics and adverse drug reactions during preclinical and clinical drug development.…”

Molecular cloning and functional characterization of the mouse organic-anion-transporting polypeptide 1 (Oatp1) and mapping of the gene to chromosome X

“…In addition, several peptidomimetic drugs such as enalapril [15], temocaprilat [16] and CRC220 [17], as well as cyclic (BQ123) [14] and linear (deltorphin) [18] peptides, are substrates of this growing family of membrane-transport proteins. A comparison between Oatp1, Oatp2 and the human OATP (OATP-A) revealed that the magnetic-resonance-imaging agent gadoxetate was only transported by Oatp1 [19], whereas digoxin was a specific compound for Oatp2 [3].…”