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Hepatic uptake of cholecystokinin octapeptide by organic anion-transporting polypeptides OATP4 and OATP8 of rat and human liver.
- Source :
-
Gastroenterology [Gastroenterology] 2001 Nov; Vol. 121 (5), pp. 1185-90. - Publication Year :
- 2001
-
Abstract
- 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.<br />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.<br />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.<br />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.
- Subjects :
- Animals
Cells, Cultured
Hepatocytes metabolism
Humans
Male
Rats
Rats, Sprague-Dawley
Solute Carrier Organic Anion Transporter Family Member 1B3
Xenopus laevis
Liver metabolism
Organic Anion Transporters physiology
Organic Anion Transporters, Sodium-Independent physiology
Sincalide pharmacokinetics
Subjects
Details
- Language :
- English
- ISSN :
- 0016-5085
- Volume :
- 121
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Gastroenterology
- Publication Type :
- Academic Journal
- Accession number :
- 11677211
- Full Text :
- https://doi.org/10.1053/gast.2001.28704