Evidence for an ATP-dependent bile acid transport protein other than the canalicular liver ecto-ATPase in rats

Luther, TT; Hammerman, Peter S.; Rahmaoui, CM; Lee, PP; Sela-Herman, Sarah; Matula, GS; Ananthanarayanan, M.; Fj, Suchy; Rr, Cavalieri; Lomri, Noureddine; Scharschmidt, B. F.

doi:10.1016/s0016-5085(97)70102-1

Cited by 10 publications

(5 citation statements)

References 2 publications

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“…179 Furthermore, the presence of an ATP-dependent taurocholate transporter other than ecto-ATPase was shown in rat hepatoma HTC cells. 180 In yeast, an ABC-type protein called BAT1 was shown to represent an ATP-dependent bile salt transporter. 181…”

Section: Canalicular Secretion Of Bile Saltsmentioning

confidence: 99%

Hepatic Transport of Bile Salts

Kullak-Ublick¹,

Stieger²,

Hagenbuch³

et al. 2000

Semin Liver Dis

269

161

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The vectorial secretion of bile salts from blood into bile is a major driving force for bile formation. The basolateral hepatocyte membrane extracts bile salts from sinusoidal blood via Na(+)-dependent and Na(+)-independent membrane transporters. Na(+)-dependent uptake of bile salts is mediated by the Na(+)-taurocholate co-transporting polypeptide, a 51-kDa protein that is exclusively expressed in hepatocytes. Na(+)-independent uptake of bile salts is mediated by the organic anion transporting polypeptides, a superfamily of multispecific bile salt and amphipathic substrate transporters. Within the hepatocyte, bile salts are bound to cytosolic proteins and traverse the cell mainly by diffusion. Transport across the canalicular membrane is the rate-limiting step in overall hepatocellular bile salt excretion and is mediated by the bile salt export pump (BSEP), a homologue of the P-glycoproteins or multidrug resistance gene products. BSEP is a vulnerable target for inhibition by estrogen metabolites, drugs such as cyclosporine A, and abnormal bile salt metabolites, all of which can cause retention of bile salts and consequently intrahepatic cholestasis. Canalicular efflux of divalent sulfated or glucuronidated bile salts is mediated by the multidrug resistance protein 2 (MRP2), which is strongly decreased in cholestasis. Decreased MRP2 expression leads to compensatory increases in the basolateral expression of MRP1 and MRP3, which mediate the sinusoidal efflux of divalent bile salt conjugates and other organic anions. Thus, the hepatocyte can regulate expression levels of individual bile salt transporters during cholestasis to evade hepatotoxic injury.

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Section: Canalicular Secretion Of Bile Saltsmentioning

confidence: 99%

Hepatic Transport of Bile Salts

Kullak-Ublick¹,

Stieger²,

Hagenbuch³

et al. 2000

Semin Liver Dis

269

161

View full text Add to dashboard Cite

show abstract

“…Indeed, the injection of poly A + RNA from these resistant cells stimulated the efflux of GCA from Xenopus laevis oocytes (Brown et al, 1995), irrespective of an endogenous transporter for the extrusion of taurocholate in oocytes (Shneider and Moyer, 1993). Moreover, the ATP-dependent transport of TC into the membrane vesicles from the resistant cells was higher than that from the parental HTC cells (Luther et al, 1997). By analyzing the poly A + RNA species from the resistant cells, BSEP cDNA can be cloned.…”

Section: Transport Of Bile Acids Across the Bile Canalicular Membranementioning

confidence: 99%

Transporters for Bile Acids and Organic Anions

Suzuki

Sugiyama

2002

Pharmaceutical Biotechnology

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“…Although canalicular ecto-ATPase has been proposed as a main regulator of canalicular secretion of bile salts (Luther et al 1997), it has been shown that levels of ecto-ATPase mRNA remain unchanged after LPS administration (Green et al 1996). Treatment with TNF-α has also been shown not to produce any effect on the activity of ecto-ATPase (Pacitti et al 1993).…”

Section: Introductionmentioning

confidence: 99%

Lipopolysaccharide alters ecto-ATP-diphosphohydrolase and causes relocation of its reaction product in experimental intrahepatic cholestasis

Zinchuk

Okada

Seguchi

2001

Cell and Tissue Research

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Lipopolysaccharide (LPS), a bacterial endotoxin, exerts profound inflammatory actions toward various tissues and cells. We induced intrahepatic cholestasis in rats by administration of LPS and followed ecto-ATP-diphosphohydrolase (ecto-apyrase) activity in the liver. The activity of the enzyme had decreased to 77% 2 h after injection compared with the activity in control animals. The maximum decrease was detected 24 h after administration. The activity was found to have partially recovered 1 week after injection, but had yet to reach control levels. In contrast to the decrease in ecto-apyrase activity, there were increases in alkaline phosphatase activity and bilirubin concentration, markers of cholestasis. In response to LPS, the reaction product of ecto-apyrase was found to relocate from the canalicular domain of the plasma membrane of hepatocytes, its predominant localization in the liver of intact animals, to the basolateral and sinusoidal domains. The pattern of histochemical reaction indicated modulation of the enzyme activity and changes in trafficking of intracellular proteins. Taken together, our findings showed that LPS administration alters ecto-apyrase and causes relocation of its reaction product from the canalicular domain of the plasma membrane of hepatocytes in the rat. It is suggested that relocation of the reaction product may be a protective mechanism to enable the hepatocytes to withstand the cytokine-induced metabolic perturbations.

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Evidence for an ATP-dependent bile acid transport protein other than the canalicular liver ecto-ATPase in rats

Cited by 10 publications

References 2 publications

Hepatic Transport of Bile Salts

Hepatic Transport of Bile Salts

Transporters for Bile Acids and Organic Anions

Lipopolysaccharide alters ecto-ATP-diphosphohydrolase and causes relocation of its reaction product in experimental intrahepatic cholestasis

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