scholarly journals Cell swelling increases bile flow and taurocholate excretion into bile in isolated perfused rat liver

1992 ◽  
Vol 281 (3) ◽  
pp. 593-595 ◽  
Author(s):  
C Hallbrucker ◽  
F Lang ◽  
W Gerok ◽  
D Häussinger
Keyword(s):  
Bile Acid ◽  
Amino Acid ◽  
Cell Volume ◽  
Rat Liver ◽  
Bile Flow ◽  
Cell Swelling ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver ◽  
Volume Changes ◽  
Close Relationship

The effects of aniso-osmotically and amino-acid-induced cell-volume changes on bile flow and biliary taurocholate excretion were studied in isolated perfused rat liver. With taurocholate (100 microM) in the influent perfusate, hypo-osmotic exposure (225 mosmol/l) increased taurocholate excretion into bile and bile flow by 42 and 27% respectively, whereas inhibition by 32 and 47% respectively was observed after hyperosmotic (385 mosmol/l) exposure. The effects of aniso-moticity on taurocholate excretion into bile was observed throughout aniso-osmotic exposure, even after completion of volume-regulatory ion fluxes and were fully reversible upon re-exposure to normo-osmotic media. Hypo-osmotic cell swelling (225 mosmol/l) increased the Vmax. of taurocholate translocation from the sinusoidal compartment into bile about 2-fold. Also, cell swelling induced by glutamine and glycine stimulated both bile flow and biliary taurocholate excretion. There was a close relationship between the aniso-osmotically and amino-acid-induced change of cell volume and taurocholate excretion into bile. The data suggest that liver cell volume plays an important role in regulating bile-acid-dependent bile flow and biliary taurocholate excretion.

scholarly journals Cell volume and bile acid excretion

1992 ◽  
Vol 288 (2) ◽  
pp. 681-689 ◽  
Author(s):  
D Häussinger ◽  
C Hallbrucker ◽  
N Saha ◽  
F Lang ◽  
W Gerok
Keyword(s):  
Amino Acids ◽  
Cell Volume ◽  
Liver Cell ◽  
Bile Flow ◽  
Cell Swelling ◽  
Isolated Perfused Rat Liver ◽  
Cell Shrinkage ◽  
Volume Changes ◽  
Close Relationship ◽  
Stimulation Of

The interaction between cell volume and taurocholate excretion into bile was studied in isolated perfused rat liver. Cell swelling due to hypo-osmotic exposure, addition of amino acids or insulin stimulated taurocholate excretion into bile and bile flow, whereas hyperosmotic cell shrinkage inhibited these. These effects were explained by changes in Vmax of taurocholate excretion into bile: Vmax. increased from about 300 to 700 nmol/min per g after cell swelling by 12-15% caused by either hypo-osmotic exposure or addition of amino acids under normo-osmotic conditions. Steady-state taurocholate excretion into bile was not affected when the influent K+ concentration was increased from 6 to 46 mM or decreased to 1 mM with iso-osmoticity being maintained by corresponding changes in the influent Na+ concentration. Replacement of 40 mM-NaCl by 80 mM-sucrose decreased taurocholate excretion into bile by about 70%; subsequent hypo-osmotic exposure by omission of sucrose increased taurocholate excretion to 160%. Only minor, statistically insignificant, effects of aniso-osmotic cell volume changes on the appearance of bolus-injected horseradish peroxidase in bile were observed. Taurocholate (400 microM) exhibited a cholestatic effect during hyperosmotic cell shrinkage, but not during hypo-osmotic cell swelling. Both taurocholate and tauroursodeoxycholate increased liver cell volume. Tauroursodeoxycholate stimulated taurocholate (100 microM) excretion into bile. This stimulatory effect was strongly dependent on the extent of tauroursodeoxycholate-induced cell swelling. During continuous infusion of taurocholate (100 microM) further addition of tauroursodeoxycholate at concentrations of 20, 50 and 100 microM increased cell volume by 10, 8 and 2% respectively, in parallel with a stimulation of taurocholate excretion into bile by 29, 27 and 9% respectively. There was a close relationship between the extent of cell volume changes and taurocholate excretion into bile, regardless of whether cell volume was modified by tauroursodeoxycholate, amino acids or aniso-osmotic exposure. The data suggest that: (i) liver cell volume is one important factor determining bile flow and biliary taurocholate excretion; (ii) swelling-induced stimulation of taurocholate excretion into bile is probably not explained by alterations of the membrane potential; (iii) bile acids modulate liver cell volume; (iv) taurocholate-induced cholestasis may depend on cell volume; (v) stimulation of taurocholate excretion into bile by tauroursodeoxycholate can largely be explained by tauroursodeoxycholate-induced cell swelling.

Endothelin-1 stimulates bile acid secretion and vesicular transport in the isolated perfused rat liver

1994 ◽  
Vol 266 (2) ◽  
pp. G324-G329 ◽  
Author(s):  
A. Tanaka ◽  
K. Katagiri ◽  
M. Hoshino ◽  
T. Hayakawa ◽  
K. Tsukada ◽  
...  
Keyword(s):  
Bile Acid ◽  
Rat Liver ◽  
Bile Flow ◽  
Low Dose ◽  
Portal Pressure ◽  
Vesicular Transport ◽  
Bile Secretion ◽  
Isolated Perfused Rat Liver ◽  
High Dose ◽  
Perfused Rat Liver

The effects of endothelin (ET) on portal pressure and bile secretion were examined using isolated perfused rat liver and rat hepatocyte preparations. ET-1 raised portal pressure dose dependently; administration at a high dose (10(-9) mol) induced a > 200% increase along with reduced bile flow and decreased secretion of bile acid and phospholipids. However, a low dose (10(-10) mol) of ET-1 brought about a < 100% portal pressure rise, enhanced both bile flow and excretion of bile acid and phospholipids, and significantly increased transfer of preadministered horseradish peroxidase (HRP) into bile. In addition, values for Ca2+ concentrations, examined by indo 1 fluorescence, were elevated in isolated hepatocytes after administration of ET-1. Papaverine suppressed the low-dose ET-1 stimulation effects on both portal pressure and bile secretion. Moreover, it also reduced the HRP excretion and suppressed intracellular Ca2+ release. This study demonstrated that ET-1 stimulates vesicular transport, probably via promotion of intracellular Ca2+ release, and, as a result, increases bile acid-dependent bile flow.

Enhancing effects of vasoconstrictors on bile flow and bile acid excretion in the isolated perfused rat liver

1996 ◽  
Vol 52 (3) ◽  
pp. 489-495
Author(s):  
Makoto Hoshino ◽  
Akitaka Tanaka ◽  
Tomihiro Hayakawa ◽  
Takayuki Ohiwa ◽  
Kenji Katagiri ◽  
...  
Keyword(s):  
Bile Acid ◽  
Rat Liver ◽  
Bile Flow ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver ◽  
Acid Excretion ◽  
Bile Acid Excretion

Effects of amino acids on bile acid-dependent and independent bile flow in the isolated perfused rat liver

1999 ◽  
Vol 30 (5) ◽  
pp. 843-849 ◽  
Author(s):  
Jean-Pascal De Bandt ◽  
Elisabeth Lasnier ◽  
Colette Rey ◽  
Colette Coudray-Lucas ◽  
Raoul Poupon ◽  
...  
Keyword(s):  
Amino Acids ◽  
Bile Acid ◽  
Rat Liver ◽  
Bile Flow ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver

scholarly journals Inhibition of proteolysis by cell swelling in the liver requires intact microtubular structures

1995 ◽  
Vol 308 (2) ◽  
pp. 529-536 ◽  
Author(s):  
S vom Dahl ◽  
B Stoll ◽  
W Gerok ◽  
D Häussinger
Keyword(s):  
Cell Volume ◽  
Rat Liver ◽  
Rat Hepatocytes ◽  
Isolated Hepatocytes ◽  
Cell Swelling ◽  
Perfused Rat Liver ◽  
Volume Changes ◽  
Isolated Rat Hepatocytes ◽  
Microtubule Inhibitors ◽  
Microtubular Structures

In the perfused rat liver, proteolysis is inhibited by cell swelling in response to hypo-osmotic media, glutamine and insulin. Colchicine, an inhibitor of microtubules, did not affect cell swelling in response to these agonists. However, the antiproteolytic action of these effectors was largely blunted in the presence of colchicine or the microtubule inhibitors colcemid and taxol. On the other hand, inhibition of proteolysis by phenylalanine, asparagine or NH4Cl, i.e. compounds which exert their antiproteolytic effects by mechanisms distinct from cell swelling, was not sensitive to colchicine. Swelling-induced inhibition of proteolysis was not affected by cytochalasin B. The anti-proteolytic effect of hypo-osmotic cell swelling and insulin was largely abolished in freshly isolated rat hepatocytes; however, it reappeared upon cultivation of the hepatocytes for 6-10 h. The restoration of the sensitivity of proteolysis to cell volume changes was accompanied by a progressive reorganization of microtubule structures, as shown by immunohistochemical staining for tubulin. It is concluded that intact microtubules are required for the control of proteolysis by cell volume, but not for the control of proteolysis by phenylalanine, asparagine or NH4Cl. These findings may explain why others [Meijer, Gustafson, Luiken, Blommaart, Caro, Van Woerkom, Spronk and Boon (1993) Eur. J. Biochem. 215, 449-454] failed to detect an antiproteolytic effect of hypo-osmotic exposure of freshly isolated hepatocytes. This effect, however, which is consistently found in the intact perfused rat liver, also reappeared in isolated hepatocytes when they were allowed to reorganize their microtubular structures in culture.

scholarly journals Regulation of cell volume in the perfused rat liver by hormones

1991 ◽  
Vol 280 (1) ◽  
pp. 105-109 ◽  
Author(s):  
S vom Dahl ◽  
C Hallbrucker ◽  
F Lang ◽  
D Häussinger
Keyword(s):  
Cell Volume ◽  
Rat Liver ◽  
Liver Cell ◽  
Intracellular Water ◽  
Cell Swelling ◽  
Perfused Rat Liver ◽  
Hormone Action ◽  
Cell Shrinkage ◽  
Volume Changes ◽  
Water Space

The effect of hormones on cell volume was studied in isolated perfused rat liver by assessing the intracellular water space as the difference between a [3H]inulin- and a [14C]urea-accessible space. The intracellular water space (control value 559 +/- 7 microliters/g of liver; n = 88) increased on addition of insulin (35 nM) or phenylephrine (5 microM) by 12 or 8% respectively, whereas it decreased with cyclic AMP (cAMP; 50 microM), glucagon (100 nM) or adenosine (50 microM) by 9, 13 or 6% respectively. Both insulin and glucagon exerted half-maximal effects on cell volume and cellular K+ balance at hormone concentrations found physiologically in the portal vein. Adenosine-induced cell shrinkage was explained by a net K+ release from the liver. Phenylephrine (5 microM) led to cell swelling by about 8%, which was additive to insulin-induced swelling. Extracellular ATP (20 microM) induced cell shrinkage by about 6%; this was additive to adenosine-induced shrinkage. Vasopressin (15 nM) did not appreciably change cell volume, but induced marked cell shrinkage when glucagon or cAMP was present. Insulin- and phenylephrine-induced cell swelling was counteracted by cAMP. Hormone-induced changes of intracellular water space could sufficiently explain accompanying liver mass changes induced by glucagon, cAMP, adenosine or vasopressin, but not those by phenylephrine and extracellular ATP. The data show that liver cell volume is subject to hormonal regulation, in part owing to modification of cellular K+ balance. Glucagon- and insulin-induced cell volume changes occur already in the presence of physiological hormone concentrations. The effects of Ca2(+)-mobilizing hormones on cell volume are not uniform. In view of the recently established role of cell volume changes in modulating liver cell function, the present findings open a new perspective on the mechanisms of hormone action in liver, underlining our previous hypothesis that cell volume changes may represent a ‘second messenger’ of hormone action.

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