Interactions of cationic drugs and cardiac glycosides at the hepatic uptake level: studies in the ratin vivo, isolated perfused rat liver, isolated rat hepatocytes and oocytes expressing oatp2

2002 ◽  
Vol 25 (4) ◽  
pp. 397-415 ◽  
Author(s):  
Dirk K. F. Meijer ◽  
Jessica E. van Montfoort

1984 ◽  
Vol 4 (10) ◽  
pp. 819-825 ◽  
Author(s):  
J. P. Monson ◽  
R. M. Henderson ◽  
J. A. Smith ◽  
R. A. Iles ◽  
M. Faus-Dader ◽  
...  

In perfused rat liver a decrease of cytosol pH, determined with pH-sensitive microelectrodes7 from 7.2 to 6.85 is associated with a 50% fall in ureogenesis from ammonium chloride. In isolated rat hepatocytes the fall in ureogenesis due to acidosis is associated with decrease in the mitochondrial and cytosolic concentration of citrulline. Limitation of carbamoyl phosphate synthesis and thus citrulline supply could be responsible for the inhibition of ureogenesis observed.



1975 ◽  
Vol 152 (1) ◽  
pp. 105-114 ◽  
Author(s):  
L Hue ◽  
F Bontemps ◽  
H Hers

1. In the isolated perfused rat liver, increasing glucose concentration from 5.5 to 55 mm in the perfusion medium caused a sequential inactivation of glycogen phosphorylase and activation of glycogen synthetase. The latter change was preceded by a lag period which corresponded to the time required to inactivate the major part of the phosphorylase. 2. The same sequence of events was observed in isolated rat hepatocytes incubated at 37°C. In this preparation, the rate of phosphorylase inactivation was greatly increased by increasing the concentration of glucose and/or of K+ ions in the external medium. The same agents also caused the activation of glycogen synthetase, but this effect was secondary to the inactivation of phosphorylase. 3. In both types of preparations, the rate of synthetase activation was modulated by the residual amount of phosphorylase a that remained after the initial phase of rapid inactivation and was independent of glucose concentration. 4. In isolated hepatocytes, the rate of conversion of glucose into glycogen was propotional to the activity of synthetase a in the preparation. This conversion was preceded by a lag period which could be shortened by increasing either glucose or K+ concentration in the medium. The incorporation of labelled glucose into glycogen was simultaneous with a glycogenolytic process which could not be attributed to the activity of phosphorylase a.



Nephron ◽  
1994 ◽  
Vol 67 (3) ◽  
pp. 334-339 ◽  
Author(s):  
Katsumi Takemura ◽  
Sohji Nagase ◽  
Kazumasa Aoyagi ◽  
Michihiro Gotoh ◽  
Akio Koyama ◽  
...  


1982 ◽  
Vol 47 (02) ◽  
pp. 166-172 ◽  
Author(s):  
Yoav Sharoni ◽  
Maria C Topal ◽  
Patricia R Tuttle ◽  
Henry Berger

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.



1991 ◽  
Vol 279 (3) ◽  
pp. 769-773 ◽  
Author(s):  
J Borensztajn ◽  
T J Kotlar ◽  
S Y Chang

Rat lymph chylomicrons and chylomicron remnants were treated with trypsin or Pronase. The ability of the resulting apoprotein-free lipoproteins to be taken up by the isolated perfused rat liver, and to bind to isolated rat liver membranes, was examined. Compared with control lipoproteins, the apoprotein-free chylomicrons and remnants retained unaltered their capacity to be differentiated by the intact liver and by the isolated membranes. Further, control remnants and apoprotein-free remnants competed for binding to the isolated membranes. We conclude that apoproteins are not required for the hepatic differentiation between chylomicrons and remnants, and suggest that the lipoprotein phospholipids may play a direct role in this process.



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