scholarly journals Temperature Effects on Radiocolloid Uptake by the Isolated Rat Liver

1957 ◽  
Vol 189 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Ralph W. Brauer ◽  
R. J. Holloway ◽  
George F. Leong
Keyword(s):  
Blood Flow ◽  
Rat Liver ◽  
Hepatic Blood Flow ◽  
Reaction Rate ◽  
Extraction Efficiency ◽  
Liver Blood Flow ◽  
Isolated Rat Liver ◽  
Isolated Rat ◽  
Unambiguous Interpretation

Effect of temperatures between 20° and 38°C on the relation between blood flow and CrPO4 colloid uptake by the isolated rat liver has been studied. The Q10 for the over-all reaction rate is substantially constant and equal to 1.92 over this range. Theoretical limitations prevent the unambiguous interpretation of this value as a measure of the Q10 of the basic uptake reaction. Hemodynamic data indicate that cooling affects liver blood flow and liver blood distribution primarily, but not exclusively, through increasing blood viscosity. Evidence pointing to possible vasorelaxation under these conditions is mentioned. The application of these results to measurements of liver blood flow in hypothermia in vivo is discussed and the required diagram relating hepatic blood flow with the product of CrPO4 extraction efficiency and hepatic blood flow for the rat is presented.

scholarly journals Hemodynamics of the Vascular Tree of the Isolated Rat Liver Preparation

1956 ◽  
Vol 186 (3) ◽  
pp. 537-542 ◽  
Author(s):  
Ralph W. Brauer ◽  
G. F. Leong ◽  
R. F. McElroy ◽  
R. J. Holloway
Keyword(s):  
Rat Liver ◽  
Liver Blood Flow ◽  
Liver Weight ◽  
Rat Plasma ◽  
Nonlinear Flow ◽  
Isolated Rat Liver ◽  
Vascular Bed ◽  
Liver Preparation ◽  
Flow Pressure ◽  
Isolated Rat

The hemodynamic properties of the hepatic vascular bed of the isolated rat liver preparation have been studied by the use of flow-pressure diagrams in experiments involving as a perfusate either whole blood or cell-free rat plasma under an oxygen partial pressure of 2.5 atm. Either perfusion medium yields a nonlinear flow-pressure diagram of sigmoid shape approaching a straight line through the origin at perfusion pressures slightly above physiological ones. Data are also reported concerning change of liver weight with perfusion pressure of the isolated organ. These, together with previously reported results of radiocolloid uptake studies, are incorporated into a representation of the hepatic vascular bed in terms of a population of parallel vascular channels having critical opening pressures distributed between 7 and 13 cm of plasma. The distribution function is described and its bearing upon liver function in relation to liver blood flow is briefly discussed.

Antiketogenic effect of glucose per se in vivo in man and in vitro in isolated rat liver cells

Metabolism ◽  
1986 ◽  
Vol 35 (7) ◽  
pp. 608-613 ◽  
Author(s):  
J.P. Riou ◽  
M. Beylot ◽  
M. Laville ◽  
L. De Parscau ◽  
J. Delinger ◽  
...  
Keyword(s):  
Rat Liver ◽  
Liver Cells ◽  
Isolated Rat Liver ◽  
Rat Liver Cells ◽  
Per Se ◽  
Effect Of Glucose ◽  
Isolated Rat

Vasopressin promotes the metabolism of near-physiological concentration of glutamine in isolated rat liver cells

1984 ◽  
Vol 4 (2) ◽  
pp. 171-176 ◽  
Author(s):  
Guy Martin ◽  
Gabriel Baverel
Keyword(s):  
Rat Liver ◽  
Liver Cells ◽  
Hepatic Gluconeogenesis ◽  
Physiological Concentration ◽  
Isolated Rat Liver ◽  
Rat Liver Cells ◽  
Isolated Rat

In isolated rat liver cells, vasopressin, like glucagon, promotes the metabolism of glutamine used at nearphysiological concentration (1 mM). These findings indicate that, in vivo, both hormones might participate in the control of hepatic gluconeogenesis and ureogenesis from glutamine.

scholarly journals Circulatory Pathways in the Rat Liver as Revealed by P32 Chromic Phosphate Colloid Uptake in the Isolated Perfused Liver Preparation

1956 ◽  
Vol 184 (3) ◽  
pp. 593-598 ◽  
Author(s):  
Ralph W. Brauer ◽  
G. F. Leong ◽  
R. F. McElroy ◽  
R. J. Holloway
Keyword(s):  
Blood Flow ◽  
Rat Liver ◽  
Transit Time ◽  
Mean Transit Time ◽  
Total Activity ◽  
Theoretical Treatment ◽  
Perfusion Rate ◽  
Isolated Rat Liver ◽  
Liver Preparation ◽  
Isolated Rat

P32-labeled chromic phosphate colloid disappears from the circulation of the isolated rat liver preparation according to a single exponential term of time. A small nonextracted contaminant, less than 3% of the total activity is also detected. At comparable blood flow rates the colloid is extracted about as completely by the isolated liver preparation as by the liver in situ in the intact animal. The efficiency with which chromic phosphate colloid is removed from perfusate passing through the isolated rat liver decreases with increasing perfusion rate. If whole blood is used as a perfusate, the efficiency of colloid extraction is almost twice as high as it is if rat blood plasma is employed, even if adequate oxygenation of the tissue is assured by high oxygen partial pressures in the latter series. A theoretical treatment of these results is given in terms of first order reaction kinetics. Agreement of experimental results with this theory at perfusion rates greater than 2 cc/gm/min. indicates that the rate of chromic phosphate colloid extraction is a function of plasma concentration of the colloid, and that the extraction efficiency for a given perfusate varies as a function of the mean transit time of perfusate through the liver. Deviations from the predictions of the theory occur at low perfusion rates, and are discussed in the light of the above concepts. A decrease of the ratio of transit time to perfusion rate under these conditions suggests a decrease in the number of channels open to blood flow at low perfusion pressures.

Effect of Liver on Lipolysis by Normal and Postheparin Sera in the Rat

1956 ◽  
Vol 185 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Judy A. Spitzer ◽  
John J. Spitzer
Keyword(s):  
Rat Liver ◽  
Lipolytic Activity ◽  
Factor Activity ◽  
Rat Serum ◽  
Oil Emulsion ◽  
Isolated Rat Liver ◽  
Normal Rat ◽  
Isolated Liver ◽  
Isolated Rat

Lipolysis by sera heparinized in vivo and by normal sera was studied after perfusion through isolated rat liver. The rate of clearing of an oil emulsion by serum containing clearing factor was decreased after perfusion through the liver. The extent of clearing was not always affected. Clearing factor activity was lessened by incubation with heparinase (prepared from rabbit livers). Normal rat serum exhibited consistent lipolytic activity following perfusion through the isolated liver. This activity was not due to clearing factor.

Uptake of plasma free fatty acids by the isolated rat liver: effect of glucagon

1963 ◽  
Vol 205 (4) ◽  
pp. 667-670 ◽  
Author(s):  
Abdullah Aydin ◽  
Joseph E. Sokal
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
Experimental System ◽  
Plasma Free Fatty Acid ◽  
Isolated Perfused Rat Liver ◽  
Isolated Rat Liver ◽  
Uptake Rates ◽  
The Difference ◽  
Isolated Rat

The uptake of oleate by the isolated perfused rat liver was studied over the range of plasma free fatty acid (FFA) concentration from 100 to 1,800 µEq/liter. Hepatic removal of FFA could be described as a linear function of the FFA concentration in blood entering the liver. When appropriate correction was made for the difference in metabolic rates of the two species, it was found that the isolated rat liver removed FFA from its perfusing blood at rates quite comparable to those reported for the dog liver in vivo. An effect of glucagon on FFA uptake rates could not be demonstrated, either with fasted or with glycogen-containing livers. This experimental system, which offers the advantages of relatively easy control of many variables and of exclusion of the effects of other organs, appears well suited for studies of fatty acid metabolism in the liver.

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