Kinetics of Nortriptyline (NT) in Rats in vivo and in the Isolated Perfused Liver: Demonstration of a ‘First Pass Disappearance’ of NT in the Liver

Pharmacology ◽  
1973 ◽  
Vol 9 (3) ◽  
pp. 177-186 ◽  
Author(s):  
C. von Bahr ◽  
O. Borgå ◽  
E. Fellenius ◽  
M. Rowland
Keyword(s):  
Perfused Liver ◽  
Isolated Perfused Liver ◽  
First Pass ◽  
Kinetics Of

scholarly journals Effect of thyroid state on cyclic AMP-mediated induction of hepatic phosphoenolpyruvate carboxykinase

1985 ◽  
Vol 226 (1) ◽  
pp. 67-73 ◽  
Author(s):  
W Höppner ◽  
W Süssmuth ◽  
H J Seitz
Keyword(s):  
Cyclic Amp ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Close Correlation ◽  
Perfused Liver ◽  
Thyroid State ◽  
Fed State ◽  
Isolated Perfused Liver ◽  
Translatable Mrna

Hepatic phosphoenolpyruvate carboxykinase (PEPCK) is significantly increased in the hyperthyroid starved rat, and moderately decreased in the hypothyroid starved rat. As tri-iodothyronine by itself has only a small and sustained effect on the induction of this enzyme, as was previously shown in the isolated perfused organ, the effect of hypo- and hyper-thyroidism on the increase in cytosolic PEPCK provoked by dibutyryl cyclic AMP (Bt2cAMP) was investigated in vivo and in the isolated perfused liver. Compared with euthyroid fed controls, in hypothyroid fed rats Bt2cAMP provoked in 2 h only a small increase in translatable mRNA coding for PEPCK. In contrast, in hyperthyroid animals PEPCK mRNA as measured by translation in vitro was already increased in the fed state, and further enhanced by Bt2cAMP injection to values as in euthyroid controls. Under all thyroid states a close correlation between PEPCK mRNA activity and PEPCK synthesis was observed. In the isolated perfused liver from the hyperthyroid fed rat, the increase in PEPCK provoked by Bt2cAMP or Bt2cAMP + isobutylmethylxanthine was considerably enhanced compared with those obtained in livers of hypothyroid rats. Also, adrenaline provoked a stimulated induction of PEPCK in hyperthyroid rats compared with hypothyroid rats. To summarize, our data indicate that the primary action of thyroid hormones on the synthesis of hepatic cytosolic PEPCK is to accelerate the cyclic AMP- or adrenaline-induction of the enzyme, acting primarily at a pretranslational level.

scholarly journals Kinetics of creatine uptake in the perfused mouse liver: a 31P-n.m.r. study of transgenic mice expressing creatine kinase (CKBB) in the liver

1994 ◽  
Vol 303 (2) ◽  
pp. 531-538 ◽  
Author(s):  
S Masson ◽  
B Quistorff
Keyword(s):  
Creatine Kinase ◽  
Transgenic Mice ◽  
Mouse Liver ◽  
Biochemical Analysis ◽  
Perfused Liver ◽  
Creatine Uptake ◽  
Total Creatine ◽  
Kinetics Of ◽  
Dependent Mechanism

Transport of creatine in the mouse liver has been investigated in vivo and in the perfused organ. Experiments were carried out with transgenic mice expressing creatine kinase in the liver (brain isoenzyme CKBB; EC 7.2.3.2.) [Koretsky, Brosnan, Chen, Chen and Van Dyke (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 3112-3116] and in the corresponding control mice. The animals were fed a regular chow with or without the addition of 10% creatine (w/w) for 5 days. The kinetics of creatine uptake was measured in the perfused liver by 31P-n.m.r. spectroscopy and biochemical analysis following infusion of creatine at concentrations ranging over 0-15 mM and at an extracellular pH of either 7.40 or 6.40. The results suggest that creatine is actively transported by a pH-dependent mechanism obeying a saturable Michaelis-Menten type of kinetics (Km = 0.80 +/- 0.18 and 5.12 +/- 2.40 mM; Vmax. = 0.57 +/- 0.04 and 1.72 +/- 0.32 mumol.g of liver-1.min-1 at pH 7.40 and 6.40 respectively). Creatine export was evaluated in the perfused liver preloaded with creatine and the results show that less than 2.5 and 5% of the total creatine pool is exported to the perfusate during 80 min of perfusion at pH 7.40 and 6.40 respectively. Taken together, these results seem to explain the observation that creatine accumulates in the mouse liver only when blood creatine is raised by creatine feeding.

Glutathione Conjugation of 4-Hydroxy-trans-2,3-nonenal in the Rat in Vivo, the Isolated Perfused Liver and Erythrocytes

1999 ◽  
Vol 159 (3) ◽  
pp. 214-223 ◽  
Author(s):  
Piet J.M. Boon ◽  
H.Susana Marinho ◽  
Roelof Oosting ◽  
Gerard J. Mulder
Keyword(s):  
Perfused Liver ◽  
Glutathione Conjugation ◽  
Isolated Perfused Liver

A comparative study of drug metabolism in the isolated perfused liver and in vivo in rats

1970 ◽  
Vol 9 (1) ◽  
pp. 99-105 ◽  
Author(s):  
C. Von Bahr ◽  
B. Alexanderson ◽  
D.L. Azarnoff ◽  
F. Sjöqvist ◽  
S. Orrenius
Keyword(s):  
Drug Metabolism ◽  
Comparative Study ◽  
Perfused Liver ◽  
Isolated Perfused Liver

Hepatic metabolism of meal-fed rats: Studies in vivo and in the isolated perfused liver

1990 ◽  
Vol 48 (2) ◽  
pp. 247-253 ◽  
Author(s):  
R.B. Bazotte ◽  
J. Constantin ◽  
N.S. Hell ◽  
A. Bracht
Keyword(s):  
Hepatic Metabolism ◽  
Perfused Liver ◽  
Isolated Perfused Liver

Influence of hepatic taurine concentration on bile acid conjugation with taurine.

1977 ◽  
Vol 232 (1) ◽  
pp. E75 ◽  
Author(s):  
W G Hardison ◽  
J H Proffitt
Keyword(s):  
Bile Acid ◽  
Cholic Acid ◽  
Sodium Cholate ◽  
Total Bile Acid ◽  
Perfused Liver ◽  
Taurine Concentration ◽  
Isolated Perfused Liver ◽  
Liver Homogenates

In vitro, addition of taurine to liver homogenates increases the proportion of cholic acid conjugated with taurine. In the present study, the relation between hepatic taurine concentration and the proportion of infused sodium cholate conjugated with taurine was studied in the whole organ. The isolated perfused liver was studied to eliminate possible transfer of taurine to or from the large extrahepatic poosl present in vivo. During cholate infusion, the proportion of taurocholate excreted in bile decreased, and the proportion of glycocholate increased in a complementary fashion. Infusion of taurine with cholate prevented these changes. Hepatic taurine concentration, calculated from measured hepatic taurine concentrations before and at the end of cholate infusion, fell. Fall in proportion of total bile acid excreted as taurocholate was most rapid at low hepatic taurine concentrations between about 1.4 and 0.65 mumol/g liver. Hepatic taurine concentrations is a major determinant of the proportion of bile acid conjugated with taurine.

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