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Bile salt-dependent flow

Stimulation of bile flow in the biliary system. The bile salt-dependent pathway, which allows bile flow, is described above. [Pg.40]

Bile salt export pump (BSEP gene symbol ABCB11) mediates the biliary excretion of nonconjugated bile salts, such as taurocholic acid, glycocholic acid and cholic acid, and therefore is responsible for the formation of the bile acid-dependent bile flow [97, 98]. Its hereditary defect results in the acquisition of PFIC2, a potentially lethal disease which requires liver transplantation [17, 81, 82, 99]. As discussed in Section 12.5.2, the inhibition of BSEP following drug administration may result in cholestasis. [Pg.297]

Bile flow and secretion are stimulated by fats and certain other foods. Bile salts may enhance or delay absorption depending on whether they form insoluble complexes with drugs or enhance the solubility of agents. [Pg.464]

The new cyclosporine formulation (Sandimmun Neoral, Novartis Pharmaceuticals Corporation, East Hanover, NJ) is a self-microemulsifying drug delivery system, which consists of the drug in a lipophilic solvent (corn oil), hydrophilic cosolvent (propylene glycol) surfactant and an antioxidant [37]. Upon contact with GI fluids, Sandimmun Neoral readily forms a homogenous, monophasic microemulsion, which allows the absorption of the drug molecules. Unlike Sandimmun, the formation of this microemulsion is independent of bile salt activity, and indeed, studies have shown that the absorption of cyclosporine from the new formulation is much less dependent on bile flow [38] and is unaffected by food intake [39],... [Pg.118]

The current proprietary cyclosporin formulation, Sandimmun Neoral, is a microemulsion formulation. Although the formulation details of the Neoral formulation are not generally available, the relative bioavailabilities of the Neoral formulation and the initial Sandimmun formulation have been reported. In a dose linearity study, the relative bioavailability of the Neoral formulation compared with the Sandimmun formulation varied from 1.74 at a 200-mg dose to 2.39 at an 800-mg dose, illustrating the usefulness of the microemulsion formulation and suggesting an approximate twofold increase in bioavailability from the microemulsion formulation [74], Further studies showed that the absorption of cyclosporin from the Neoral formulation was significantly less variable [75] and less dependent on bile flow [76] than oral Sandimmun and that its absorption was unaffected by food [77], In terms of its apparent lack of reliance on bile for absorption, it is not known whether cyclosporin is absorbed from the formulation directly or just requires much lower bile salt concentrations to facilitate absorption. [Pg.99]

People of western culture ingest about 100 g of triacylglycerol per day. The digestion and absorption of this lipid, together with the ingested phospholipids, depend on secretions from the pancreas (exocrine) and a flow of bile from the gall-bladder. The important constituents of the pancreatic secretions are enzymes, and those of the bile are the bile salts (Chap. 6). [Pg.362]

The bile salt-independent pathway depends on osmotically active solutes such as glutathione and bicarbonate to generate water flow into the canaliculi. It has been shown that bile flow continues at zero bile salt excretion, i.e. a bile salt-independent process. [Pg.39]

The bile acid-dependent fraction (250 ml) is formed chiefly in the periportal acinus, (s. tab 3.2) There is a linear relationship between bile acid excretion and bile flow. Osmotic filtration of water and inorganic ions is proportionally elevated (dependent upon bile salt concentration). Other secretory mechanisms or pump systems may also be activated by bile acids. [Pg.37]

Stasis is, by definition, a diminution in the normal rate of bile flow, which appears to be necessary for the removal of potential gallstone nidi. This flow is initially determined primarily by bile salt secretion from the hepatocyte, but secretion by ductular cells and reabsorption of fluid and electrolytes by biliary tract epithelium are also important factors. In species with gallbladders, flow in this organ also depends on its filhng passively and then emptying by muscular contraction. In all cases, flow can be diminished by mechanical obstruction, and most of the early work with stasis mentioned... [Pg.159]

BSEP is a liver-specific and ATP-dependent transport protein that mediates the excretion of bile salts into bile and is expressed on the apical plasma membrane domain (canalicular surface) of hepatocytes (Lam et al., 2010). Bile formation and excretion is an essential biological process in higher vertebrates and is an important route of xenobiotic elimination, which also plays a key role in intestinal dissolution and absorption of lipids, vitamins, and fat-soluble food components. Bile salts are synthesized within hepatocytes by cytochrome P450-mediated metabolism of cholesterol and are key components of bile (Hofmann and Hagey, 2008). Bile formation and bile flow are regulated physiologically by complex mechanisms, which in hepatocytes include nuclear hormone receptor-mediated transcriptional pathways and a variety of posttranscriptional processes (Kullak-Ublick et al., 2004 Gonzalez, 2012). [Pg.102]


See other pages where Bile salt-dependent flow is mentioned: [Pg.366]    [Pg.2710]    [Pg.290]    [Pg.96]    [Pg.407]    [Pg.337]    [Pg.91]    [Pg.679]    [Pg.283]    [Pg.303]    [Pg.348]    [Pg.371]    [Pg.422]   
See also in sourсe #XX -- [ Pg.89 ]




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