Determination of antiviral nucleoside analogues AM365 and AM188 in perfusate and bile of the isolated perfused rat liver using HPLC

Ouabain exhibits a dose-dependent choleretic effect in the isolated perfused rat liver. Its uptake from the perfusate into the liver is maintained against a concentration gradient and becomes clearly saturated at higher perfusate concentrations. A low extracellular sodium concentration inhibits the rate of ouabain transfer into liver cells, resulting in a marked decrease of the maximal transport rate. Dibucaine completely abolishes the uptake of the glycoside by the isolated liver. Determination of Na-22 tracer fluxes suggests that ouabain uptake is accompanied by a net flux of sodium into the cell, which seems to be due to a cotransport of sodium with ouabain rather than to the inhibition of the sinusoidal Na+ -K+ -ATPase. Sodium introduced into the cell in this way apparently is extruded into the bile canaliculi. The increase of isotonic bile flow, which is simultaneously observed, points to a dilution of the canalicular sodium gradient by water and electrolytes through an intercellular pathway. Our results present further evidence that bile secretion is controlled by transcellular sodium movements.

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A Comparison of Plasminogen Activators Derived from Rat Plasma, Primary Rat Hepatocytes and Isolated Perfused Rat Liver

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657155 ◽

1982 ◽

Vol 47 (02) ◽

pp. 166-172 ◽

Cited By ~ 4

Author(s):

Yoav Sharoni ◽

Maria C Topal ◽

Patricia R Tuttle ◽

Henry Berger

Keyword(s):

Rat Liver ◽

Isoelectric Point ◽

Rat Hepatocytes ◽

Cell Types ◽

Plasminogen Activators ◽

Rat Plasma ◽

Isolated Perfused Rat Liver ◽

Perfused Rat Liver ◽

Molecular Weights ◽

Physiological Relevance

SummaryOf the two cell types it was possible to culture from the dissociated rat liver, hepatocytes and Kupffer cells, only the former were fibrinolytically active. Rat hepatocytes during the first 24 hr in culture secreted two plasminogen activators with molecular weights identical to those found in rat plasma, an 80,000-dalton form (PA-80) and a 45,000-dalton form (PA-45). Partially purified preparations of plasminogen activators from both sources were subjected to isoelectric focusing (IEF) to compare characteristics further. There were three distinct peaks of PA-45 in each preparation with isoelectric points of 7.1, 7.2 and 7.4; all electrophoretic forms had the same low affinity to fibrin. PA-80 from both sources displayed similar IEF profiles with forms ranging from pH values of 7 to 8, all with the same high affinity to fibrin. The major form of PA-80 in the plasma preparation had an isoelectric point of 7.9 whereas that in the hepatocyte preparation had an isoelectric point of 7.6. The isolated perfused rat liver was also shown to produce both PA-80 and PA-45 emphasizing the physiological relevance of the findings with hepatocytes. It is concluded that in the rat hepatocytes contribute to the plasma profile with regard to the plasminogen activator content.

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