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Expression of sodium-independent organic anion uptake systems of skate liver in Xenopus laevis oocytes

Jacquemin, E. and Hagenbuch, B. and Wolkoff, A. W. and Meier, P. J. and Boyer, J. L.. (1995) Expression of sodium-independent organic anion uptake systems of skate liver in Xenopus laevis oocytes. American journal of physiology. Gastrointestinal and liver physiology, Vol. 268, H. 1 , G18-G23.

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Official URL: http://edoc.unibas.ch/dok/A5261746

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Abstract

The expression of the basolateral sodium-independent organic anion uptake system of the little skate (Raja erinacea) has been studied in Xenopus laevis oocytes. Injection of oocytes with skate liver poly(A)+ RNA resulted in the functional expression of chloride-dependent sulfobromophthalein (BSP) uptake and sodium-independent taurocholate uptake within 3-5 days. The expressed chloride-dependent BSP uptake activity exhibited saturation kinetics [apparent Michaelis constant (Km) 1.8 microM] and efficiently extracted BSP from its binding sites on bovine serum albumin. The chloride-sensitive portion of BSP uptake was inhibited by bilirubin (10 microM; 27%), 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (100 microM; 57%), bumetanide (100 microM; 48%), taurocholate (200 microM; 51%), and cholate (200 microM; 45%). Size fractionation of total skate liver mRNA revealed that a 1.8- to 2.9-kb size class mRNA was sufficient to express chloride-dependent BSP uptake and sodium-independent taurocholate uptake. In addition, a 1- to 1.7-kb size class mRNA expressed sodium-independent taurocholate uptake but had no effects on BSP uptake. This study confirms that an organic anion transport system for chloride-dependent BSP uptake, with characteristics similar to rat liver, is already expressed in the liver of lower vertebrates and thus represents a phylogenetically old system. Sodium-independent taurocholate uptake in skate liver may be mediated by two different transport systems.
Faculties and Departments:11 Rektorat und Verwaltung > Vizerektorat Forschung
UniBasel Contributors:Meier-Abt, Peter J.
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Physiological Society
ISSN:0002-9513
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:22 Mar 2012 14:21
Deposited On:22 Mar 2012 13:23

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