Chloride transport by intact rat liver and cultured rat hepatocytes

Scharschmidt, Bruce F.; Dyke, Rebecca W. Van; Stephens, J. E.

doi:10.1152/ajpgi.1982.242.6.g628

Cited by 13 publications

(18 citation statements)

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“…Experimental systems Isolated perfused rat liver. The surgical techniques, design, and operation of the perfused rat liver apparatus used in these studies have been described in detail previously (17)(18)(19). A constant perfusion rate of 25 ml/min was maintained in all studies and net portal perfusion pressure was <5 cm H20 during all experiments.…”

Section: Analytical and Preparative Techniquesmentioning

confidence: 99%

“…This system using perfusate containing 20% (vol/vol) fluorocarbon emulsion (Fluosol-43) as an oxygen carrier has been extensively validated. Viability of the perfused liver for perfusions up to 3 h has been shown by normal appearance by electron microscopy, stable perfusate lactate dehydrogenase and transaminase activity, and normal hepatic oxygen consumption (17)(18)(19).…”

Section: Analytical and Preparative Techniquesmentioning

confidence: 99%

“…The first 30 min represented a stabilization period in which the liver was perfused with bile acid-free and marker-free fluorocarbon-containing perfusate. At 30 min, a new perfusate containing appropriate marker(s) was abruptly introduced into the system as previously described (17)(18)(19) so as to produce a "square-wave" increase in marker concentration.…”

Section: Analytical and Preparative Techniquesmentioning

confidence: 99%

“…At 75 min, marker was flushed from the system by a 2-min period of nonrecirculating perfusion with marker-free Krebs-Hensleit buffer followed by 43 min of recirculating perfusion with marker-free perfusate in a fashion similar to that previously employed for ion substitution experiments (17)(18)(19). Finally, to assess the possible effect of bile acids on washout of residual liver-associated marker, a 2.5-Mmol bolus of taurocholate was introduced at 120 min followed by taurocholate infusion for the final 30 min (18).…”

Section: Analytical and Preparative Techniquesmentioning

confidence: 99%

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Biliary secretion of fluid-phase markers by the isolated perfused rat liver. Role of transcellular vesicular transport.

et al. 1985

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In these studies, we have used several approaches to systematically explore the contribution of transcellular vesicular transport (transcytosis) to the blood-to-bile movement of inert fluid-phase markers of widely varying molecular weight. First, under steady-state conditions, the perfused rat liver secreted even large markers in appreciable amounts. The bile-to-plasma (B/P) ratio of these different markers, including microperoxidase (B/P ratio = 0.06; mol wt = 1,879), inulin (B/P ratio = 0.09, mol wt = 5,000), horseradish peroxidase (B/P ratio = 0.04, mol wt = 40,000), and dextran (B/P ratio = 0.09, mol wt = 70,000), exhibited no clear ordering based on size alone, and when dextrans of two different sizes (40,000 and 70,000 mol wt) were studied simultaneously, the relative amounts of the two dextran species in bile were the same as in perfusate. Taurocholate administration produced a 71% increase in bile flow but little or no (0-20%) increase in the output of horseradish peroxidase, microperoxidase, inulin, and dextran. Second, under nonsteady-state conditions in which the appearance in or disappearance from bile of selected markers was studied after their abrupt addition to or removal from perfusate, erythritol reached a B/P ratio of 1 within 2 min. Microperoxidase and dextran appeared in bile only after a lag period of 12 min and then slowly approached maximal values, whereas sucrose exhibited kinetically intermediate behavior. A similar pattern was observed after removal of >95% of the marker from the perfusate. Erythritol rapidly reapproached a B/P ratio of 1, whereas the B/P ratio for sucrose, dextran, and microperoxidase fell much more slowly and exceeded 1 for a full 30 min after perfusate washout. Finally, electron microscopy and fluorescence microscopy of cultured hepatocytes demonstrated the presence of horseradish peroxidase and fluoresceindextran, respectively, in intracellular vesicles, and fractionation of perfused liver homogenates revealed that at least 35-50% of sucrose, inulin, and dextran was associated with subcellular organelles.Collectively, these observations are most compatible with a transcytosis pathway that contributes minimally to the secretion of erythritol, but accounts for a substantial fraction of sucrose secretion and virtually all (>95%) of the blood-to-bile

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Section: Analytical and Preparative Techniquesmentioning

confidence: 99%

Section: Analytical and Preparative Techniquesmentioning

confidence: 99%

Section: Analytical and Preparative Techniquesmentioning

confidence: 99%

Section: Analytical and Preparative Techniquesmentioning

confidence: 99%

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Biliary secretion of fluid-phase markers by the isolated perfused rat liver. Role of transcellular vesicular transport.

et al. 1985

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“…This evidence includes the observations that removal ofperfusate HCO (but not C-) decreases basal bile formation by perfused liver (1)(2)(3)(4) and that certain bile acids, such as ursodeoxycholic acid produce a severalfold increase in bile flow and an increase in biliary HCO3 concentration to levels two to three times that present in plasma or perfusate (5)(6)(7). licular membrane (10).…”

Section: Introductionmentioning

confidence: 96%

Rat hepatocytes exhibit basolateral Na+/HCO3- cotransport.

et al. 1989

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Techniques for Studying Biliary Secretion: Electrolytes in Bile

Bear

Strasberg

1984

Hepatology

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A major limitation in understanding bile formation has been technical. The liver and ductular epithelium are relatively inaccessible, necessitating indirect techniques of uncertain validity. This is well seen in attempts to define the role of electrolyte secretion in bile. It is widely agreed that bile salts stimulate a component of canalicular flow and that inorganic electrolyte secretion is stimulated by bile salts. The choleretic efficiency of a bile salt is directly related to the magnitude of the electrolyte effect. But there is no consensus regarding how and where bile salts stimulate electrolyte secretion. Some evidence points to a paracellular route by processes of solvent drag and diffusion. Other studies suggest stimulation of specific transcellular electrolyte pathways. It has been believed that canalicular bile salt-independent bile flow is generated by active blood-to-bile electrolyte transport. Actually, available methods do not permit us to conclude with absolute certainty that there is canalicular bile salt-independent flow, although there is considerable evidence for it. New studies suggest that electrolyte transport in this type of flow is passive and that flow is due to transport of organic anions. Ductular flow does seem to be due to active transport of electrolytes, particularly bicarbonate. Better and more direct techniques are required to settle the controversies in this area.To understand the formation of a secretion such as bile one would like to be able to answer several questions. What is the force generating the flow (osmotic or hydrostatic)? What solutes does the epithelium concentrate in order to create osmotic gradients? Where is the energy for such transport derived? Does concentration occur by active transport or creation of electrical gradients? What secondary effects on movement of other solutes are induced (diffusional or solvent drag)? Where do the solutes cross the epithelial barrier (through or between cells) and what are the specific transporting mechanisms for transcellular transport?Bile is formed by two epithelial barriers in series, the hepatocyte epithelium and the ductular epithelium. The complex processes of solute and water transport occur at both loci. The investigator of bile flow physiology is limited to obtaining samples distal to the two sites of water and solute secretion or he must study the secretory processes in liver cells or membranes. Micropuncture of microscopic secretory or collecting channels or isolation of secretory units such as lengths of ductular epithelium are not yet technically possible, unlike in studies of urine formation.To circumvent these shortcomings, ingenious but freAddress reprint requests to:

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Chloride transport by intact rat liver and cultured rat hepatocytes

Cited by 13 publications

References 0 publications

Biliary secretion of fluid-phase markers by the isolated perfused rat liver. Role of transcellular vesicular transport.

Biliary secretion of fluid-phase markers by the isolated perfused rat liver. Role of transcellular vesicular transport.

Rat hepatocytes exhibit basolateral Na+/HCO3- cotransport.

Techniques for Studying Biliary Secretion: Electrolytes in Bile

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