RGD Reference Report - Hepatic uptake of cholecystokinin octapeptide by organic anion-transporting polypeptides OATP4 and OATP8 of rat and human liver. - Rat Genome Database

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Hepatic uptake of cholecystokinin octapeptide by organic anion-transporting polypeptides OATP4 and OATP8 of rat and human liver.

Authors: Ismair, MG  Stieger, B  Cattori, V  Hagenbuch, B  Fried, M  Meier, PJ  Kullak-Ublick, GA 
Citation: Ismair MG, etal., Gastroenterology. 2001 Nov;121(5):1185-90.
RGD ID: 2303133
Pubmed: (View Article at PubMed) PMID:11677211

BACKGROUND & AIMS: Cholecystokinin (CCK) is a major gastrointestinal peptide hormone that is released postprandially from the small intestine and exerts marked effects on gallbladder and gastrointestinal motility. The smaller isoforms CCK-8 and CCK-4 are rapidly taken up into hepatocytes, metabolized, and excreted into bile. Our aim was to identify and characterize the hepatocellular CCK-8 uptake system. METHODS: CCK-8 uptake was measured in Xenopus laevis oocytes expressing the organic anion-transporting polypeptides of rat liver (Oatp1, Oatp2, Oatp3, or Oatp4) and of human liver (OATP-A, OATP-B, OATP-C, or OATP8) and in primary cultured rat hepatocytes. RESULTS: Rat Oatp4 and human OATP8 efficiently mediated CCK-8 uptake in oocytes, with Michaelis constant (Km) values of 14.9 +/- 2.9 micromol/L and 11.1 +/- 2.9 micromol/L, respectively. CCK-8 uptake by hepatocytes was also saturable, with a Km of 6.7 +/- 2.1 micromol/L. The Km value in rat hepatocytes is consistent with Oatp4-mediated transport. CONCLUSIONS: CCK-8 is selectively transported by rat Oatp4 and human OATP8, both of which are exclusively expressed at the basolateral membrane of hepatocytes. These 2 transporters are the first and probably the predominant hepatic uptake systems for CCK-8 and may be critical for the rapid clearance of this hormone from the circulation.



Gene Ontology Annotations    

Biological Process

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Slco1b2  (solute carrier organic anion transporter family member 1B2)


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