Lack of Uptake and Oxidation of Chylomicron Triglyceride to Carbon Dioxide and Ketone Bodies by the Perfused Rat Liver

Nature ◽  
1965 ◽  
Vol 206 (4980) ◽  
pp. 195-196 ◽  
Author(s):  
J. M. FELTS ◽  
P. A. MAYES
Keyword(s):  
Carbon Dioxide ◽  
Rat Liver ◽  
Ketone Bodies ◽  
Perfused Rat Liver ◽  
Chylomicron Triglyceride

scholarly journals Rates of ketone-body formation in the perfused rat liver

1969 ◽  
Vol 112 (5) ◽  
pp. 595-600 ◽  
Author(s):  
H. A. Krebs ◽  
Patricia G. Wallace ◽  
R. Hems ◽  
R. A. Freedland
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Ketone Bodies ◽  
Short Chain Fatty Acids ◽  
Diabetic Rats ◽  
Isolated Perfused Rat Liver ◽  
Perfused Liver ◽  
Perfused Rat Liver ◽  
Normal Range ◽  
Physiological Value

1. The rates of formation of acetoacetate and β-hydroxybutyrate by the isolated perfused rat liver were measured under various conditions. 2. The rates found after addition of butyrate, octanoate, oleate and linoleate were about 100μmoles/hr./g. wet wt. in the liver of starved rats. These rates are much higher than those found with rat liver slices. 3. The differences between the rates given by slices and by the perfused organ were much higher with the long-chain than with short-chain fatty acids. The increments caused by oleate and linoleate were 12 and 16 times as large in the perfused organ as in the slices, whereas the increments caused by butyrate and octanoate were about four times as large. 4. The rates of ketogenesis in the unsupplemented perfused liver of well-fed rats, and the increments caused by the addition of fatty acids, were about half of those in the liver from starved rats. 5. The value of the [β-hydroxybutyrate]/[acetoacetate] ratio of the medium was raised by octanoate, oleate and linoleate. 6. Carnitine did not significantly accelerate ketogenesis from fatty acids. 7. Oleate formed up to 82% of the expected yield of ketone bodies. 8. In the liver of alloxan-diabetic rats the endogenous rates of ketogenesis were raised, in some cases as high as in the liver from starved rats, after addition of oleate. 9. On addition of either β-hydroxybutyrate or acetoacetate to the perfusion medium the liver gradually adjusted the [β-hydroxybutyrate]/[acetoacetate] ratio towards the normal range. 10. The [β-hydroxybutyrate]/[acetoacetate] ratio of the medium was about 0·4 when slices were incubated, but near the physiological value of 2 when the liver was perfused. 11. The experiments demonstrate that for the study of ketogenesis slices are in many ways grossly inferior to the perfused liver.

scholarly journals Fatty acid metabolism in the perfused rat liver

1970 ◽  
Vol 119 (3) ◽  
pp. 525-533 ◽  
Author(s):  
H. A. Krebs ◽  
R. Hems
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Ketone Body ◽  
Unsaturated Fatty Acids ◽  
Ketone Bodies ◽  
Saturated Fatty Acids ◽  
Perfused Rat Liver ◽  
Body Formation ◽  
Body Production ◽  
Chain Fatty Acids

1. The formation of acetoacetate, β-hydroxybutyrate and glucose was measured in the isolated perfused rat liver after addition of fatty acids. 2. The rates of ketone-body formation from ten fatty acids were approximately equal and independent of chain length (90–132μmol/h per g), with the exception of pentanoate, which reacted at one-third of this rate. The [β-hydroxybutyrate]/[acetoacetate] ratio in the perfusion medium was increased by long-chain fatty acids. 3. Glucose was formed from all odd-numbered fatty acids tested. 4. The rate of ketone-body formation in the livers of rats kept on a high-fat diet was up to 50% higher than in the livers of rats starved for 48h. In the livers of fat-fed rats almost all the O2 consumed was accounted for by the formation of ketone bodies. 5. The ketone-body concentration in the blood of fat-fed rats rose to 4–5mm and the [β-hydroxybutyrate]/[acetoacetate] ratio rose to 11.5. 6. When the activity of the microsomal mixed-function oxidase system, which can bring about ω-oxidation of fatty acids, was induced by treatment of the rat with phenobarbitone, there was no change in the ketone-body production from fatty acids, nor was there a production of glucose from even-numbered fatty acids. The latter would be expected if ω-oxidation occurred. Thus ω-oxidation did not play a significant role in the metabolism of fatty acids. 7. Arachidonate was almost quantitatively converted into ketone bodies and yielded no glucose, demonstrating that gluconeogenesis from poly-unsaturated fatty acids with an even number of carbon atoms does not occur. 8. The rates of ketogenesis from unsaturated fatty acids (sorbate, undecylenate, crotonate, vinylacetate) were similar to those from the corresponding saturated fatty acids. 9. Addition of oleate together with shorter-chain fatty acids gave only a slightly higher rate of ketone-body formation than oleate alone. 10. Glucose, lactate, fructose, glycerol and other known antiketogenic substances strongly inhibited endogenous ketogenesis but had no effects on the rate of ketone-body formation in the presence of 2mm-oleate. Thus the concentrations of free fatty acids and of other oxidizable substances in the liver are key factors determining the rate of ketogenesis.

Lipogenesis from ketone bodies in the perfused rat liver: effects of acetate and ethanol

1987 ◽  
Vol 65 (11) ◽  
pp. 989-996 ◽  
Author(s):  
Gerda Endemann ◽  
Patrick G. Goetz ◽  
John F. Tomera ◽  
William M. Rand ◽  
Sylvain Desrochers ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Ketone Body ◽  
Ketone Bodies ◽  
The Other ◽  
Ethanol Metabolism ◽  
Perfused Rat Liver ◽  
Other Hand

The interactions between acetate or ethanol metabolism, lipogenesis, and ketone body utilization have been studied in isolated livers from fed rats perfused with 15 mM glucose and 10 mM acetate or ethanol. The contribution of acetate to ketogenesis is constant; on the other hand, the contribution of ethanol to ketogenesis increases with time, presumably because of the accumulation of acetate in the perfusate. Ketogenesis is decreased in the presence of ethanol (but not acetate), while ketone body utilization is not affected by ethanol or acetate. Acetate contributes one third and ethanol contributes one half of the carbon incorporated into fatty acids and 3-β-hydroxysterols. Only a small fraction (less than 5%) of the incorporation of acetate or ethanol into fatty acids and sterols occurs via transient incorporation into ketone bodies.

scholarly journals Effects of Dietary Soybean Peptides on Hepatic Production of Ketone Bodies and Secretion of Triglyceride by Perfused Rat Liver

2007 ◽  
Vol 71 (10) ◽  
pp. 2451-2457 ◽  
Author(s):  
Shizuka TAMARU ◽  
Takayuki KURAYAMA ◽  
Masanobu SAKONO ◽  
Nobuhiro FUKUDA ◽  
Toshihiro NAKAMORI ◽  
...  
Keyword(s):  
Rat Liver ◽  
Ketone Bodies ◽  
Perfused Rat Liver

Liver Blood Flow as a Major Determinant of the Clearance of Recombinant Human Tissue-Type Plasminogen Activator

1992 ◽  
Vol 67 (01) ◽  
pp. 083-087 ◽  
Author(s):  
A de Boer ◽  
C Kluft ◽  
J M Kroon ◽  
F J Kasper ◽  
H C Schoemaker ◽  
...  
Keyword(s):  
Blood Flow ◽  
Rat Liver ◽  
Healthy Subjects ◽  
Liver Blood Flow ◽  
Major Determinant ◽  
Tissue Type ◽  
Perfused Rat Liver ◽  
Liver Model ◽  
Type Plasminogen Activator ◽  
Proportional Change

SummaryThe influence of changes in liver blood flow on the clearance of rt-PA was studied both in healthy subjects and in a perfused rat liver model. Liver blood flow in healthy subjects was documented indirectly by the clearance of indocyanine green (ICG). Exercise reduced liver blood flow on average by 57% with a 95% confidence interval (95% Cl) ranging from 51% to 62% (n = 5) and increased plasma levels of rt-PA activity (after an i. v. infusion of 18 mg of rt-PA over 120 min) by 119% (95% Cl, 58% - 203%) and rt-PA antigen by 91% (95% Cl, 30% - 140%). In the perfused rat liver model it was shown that halving or doubling of the physiological flow rate of a perfusate, containing rt-PA caused a proportional change in the clearance of rt-PA, while the extraction of rt-PA by the liver remained similar. In conclusion, liver blood flow is a major determinant of the clearance of rt-PA. This may have important implications for dosage of rt-PA in patients with myocardial infarction.

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

1982 ◽  
Vol 47 (02) ◽  
pp. 166-172 ◽  
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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