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Hepatic Uptake of the Magnetic Resonance Imaging Contrast Agent Gadoxetate by the Organic Anion Transporting Polypeptide Oatp1
Gadoxetate is a new hepatobiliary magnetic resonance imaging contrast agent. It is specifically taken up by hepatocytes, and its uptake can be inhibited by the coadministration of bromosulfophthalein, suggesting an involvement of one or several of the cloned organic anion transporting polypeptides O...
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Published in: | The Journal of pharmacology and experimental therapeutics 1999-07, Vol.290 (1), p.153-157 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | Gadoxetate is a new hepatobiliary magnetic resonance imaging contrast agent. It is specifically taken up by hepatocytes, and
its uptake can be inhibited by the coadministration of bromosulfophthalein, suggesting an involvement of one or several of
the cloned organic anion transporting polypeptides Oatp1, Oatp2, and/or OATP. In this study, we demonstrated saturable uptake
of gadoxetate by Oatp1 cRNA-injected Xenopus laevis oocytes ( K m â¼ 3.3 mM). In contrast, gadoxetate was not taken up by Oatp2 or OATP cRNA-injected oocytes. Oatp1-mediated gadoxetate uptake
(100 μM) could be inhibited by 10 μM bromosulfophthalein (45%), 200 μM taurocholate (92%), 100 μM rifamycin SV (97%), and
100 μM rifampicin (51%). These results show that gadoxetate is a low-affinity substrate of Oatp1. Oatp1-mediated gadoxetate
transport demonstrated a similar apparent K m value and cis -inhibition pattern as previously determined in rats in vivo, indicating that Oatp1 is significantly involved in gadoxetate
uptake into rat liver. |
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ISSN: | 0022-3565 1521-0103 |