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 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 Variation of Fatty Acids and Antioxidants Contents of Vegetarian Rayeb Milk as Affected by Fortification with Natural and Artificial Sweeteners

2020 ◽  
pp. 1-9
Author(s):  
Magdy Mohamed Ismail ◽  
Magdy Mohamed Ismail ◽  
Mohamed Abdou Mousa ◽  
Mohamed Ismail Abou-Dobara ◽  
Nawal Mohamed Refat
Keyword(s):  
Fatty Acids ◽  
Antioxidant Activity ◽  
Volatile Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Essential Fatty Acids ◽  
Saturated Fatty Acids ◽  
Cow Milk ◽  
Omega 3 ◽  
Milk Mixture ◽  
Chain Fatty Acids

Rayeb milk (bio-stirred yogurt) samples were prepared from cow milk sesame milk or cow and sesame milk mixture (1:1) with or without adding sucrose (5%), honey (5%), fructose (2.5%) and sorbitol (1.5%) and using ABT-5 culture. Results showed levels of saturated fatty acids (SFA), short chain fatty acids (SCFA) and medium chain fatty acids (MCFA were lower whereas values of unsaturated fatty acids (USFA), monounsaturated fatty acids (MUSFA), polyunsaturated fatty acids (PUSFA) and long chain fatty acids (LCFA) were higher in sesame milk Rayeb than that of Rayeb manufactured from cow milk. Rayeb made from cow and sesame mixture had higher levels of antioxidant activity than Rayeb prepared from cow milk or sesame milk. The acidity, total solids and total volatile fatty acids values of Rayeb milk treatments contained sweeteners were higher than that of control. The addition of sweeteners decreased SFA, SCFA and MCFA and increased USFA, MUSFA, PUSFA, LCFA and antioxidant activity values of Rayeb milk. Essential fatty acids, linoleic acid (omega-6), α-linolenic acid (omega-3) and oleic acid (omega-9) greatly increased in Rayeb made from cow and sesame milk mixture. Adding sweeteners had the same effect. Fortification of Rayeb milk with sweeteners highly improved the smell, taste, mouth feel, texture and body evaluation scores.

Influencia de la clarificación por sedimentación en el contenido de ácidos grasos en mostos garnacha y Viura y su evolución durante la fermentación / Influence of clarification by sedimentation on the content of fatty acids in garnacha and Viura musts and their changes during the fermentation

1999 ◽  
Vol 5 (6) ◽  
pp. 471-478
Author(s):  
D. Torrea Goñi ◽  
A. García Sotro ◽  
C. Ancín Azpilicueta
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Control Sample ◽  
High Rate ◽  
Long Chain Fatty Acids ◽  
Sugar Consumption ◽  
Long Chain ◽  
Rate Of Consumption ◽  
Chain Fatty Acids

The influence of static sedimentation of garnacha and Viura musts on the concentration of fatty acids and their changes during fermentation is evaluated. A non-sedimented must was used as a control sample. The sedimentation of garnacha must reduced the concentration of saturated fatty acids (mainly stearic acid), although it did not totally eliminate any single one. During the first half of the fermen tation (up to 50% of sugar consumption) the medium-chain fatty acids excreted their highest concen tration in the sample being clarified. The long-chain fatty acids, both saturated and unsaturated, were consumed in both samples, although the saturated acids showed a higher rate of consumption in the contrul sample (57%) than in the sedimented sample (10%). The polyunsaturated fatty acids were consumed at a high rate in both samples. During the second half of the fermentation (from 50% sugar consumption until the end of the fermentation) the consumption of long-chain fatty acids, both saturated and unsaturated, was similar in the control sample and in the sedimented sample. The clarification of the Viura must reduced all the above unsaturated fatty acids, particularly linoleic (84%). In the first half of the fermentation, the consumption of long-chain fatty acids, both saturated and unsaturated, was greater in the control sample than in the sedimented sample; the same oc curred during the second half of the fermentation.

The development of the digestive system of the young animal. VI. The metabolism of short-chain fatty acids by the rumen and caecal wall of the young lamb

1962 ◽  
Vol 59 (3) ◽  
pp. 375-379 ◽  
Author(s):  
D. M. Walker ◽  
R. A. Simmonds
Keyword(s):  
Fatty Acids ◽  
Ketone Body ◽  
Young Animal ◽  
Marked Change ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Newborn Lamb ◽  
Adult Sheep ◽  
Body Production ◽  
Chain Fatty Acids

1. Rumen and caecal wall tissues were taken at slaughter from lambs varying in age from newborn to 11 weeks. The ability of these tissues to metabolize the short-chain fatty acids, acetic, propionic and butyric acid was compared with tissues from adult sheep. Ketone body production was measured.2. The utilization of butyrate by the rumen wall in the newborn lamb was lower than in the adult, but exceeded the adult levels at 3 weeks of age and maintained this higher utilization to 11 weeks and probably longer. Ketone body production was negligible at birth but followed butyrate utilization closely thereafter.3. The caecal wall in the newborn lamb utilized butyrate at a much higher rate than the adult sheep tissue. Foetal lamb caecal tissue utilized butyrate to the same extent as in the newborn lamb. Levels were, however, typical of the adult within a day or two of birth and showed no subsequent effect of age. Ketone body production was negligible at all ages.4. Rumen development in milk-fed lambs slaughtered at 7 and 9 weeks of age was retarded anatomically and showed decreased capacity in the utilization of butyrate.5. The utilization of acetate and propionate by rumen and caecal tissues showed no marked change due to age. Ketone body production from these acids was low.

scholarly journals Young women partition fatty acids towards ketone body production rather than VLDL-TAG synthesis, compared with young men

2011 ◽  
Vol 105 (6) ◽  
pp. 857-865 ◽  
Author(s):  
Kyriakoula Marinou ◽  
Martin Adiels ◽  
Leanne Hodson ◽  
Keith N. Frayn ◽  
Fredrik Karpe ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Young Women ◽  
Metabolic Profile ◽  
Ketone Body ◽  
Ketone Bodies ◽  
Young Men ◽  
Isotopic Enrichment ◽  
Plasma Nefa ◽  
Lower Plasma Glucose ◽  
Body Production

Before the menopause, women are relatively protected against CVD compared with men. The reasons for this sex difference are not completely understood, but hepatic fatty acid metabolism may play a role. The present study aimed to investigate the utilisation of plasma NEFA by the liver and to determine whether they are partitioned differently into ketone bodies and VLDL-TAG in healthy, lean young men and women. Volunteers were studied during a prolonged overnight fast (12–19 h) using an intravenous infusion of [U-13C]palmitate. After 12 h fasting, the women had a more advantageous metabolic profile with lower plasma glucose (P < 0·05) and TAG (P < 0·05) but higher plasma NEFA (P < 0·05) concentrations. Plasma 3-hydroxybutyrate (3-OHB) concentrations rose more in women than in men, and the transfer of13C from [U-13C]palmitate to plasma [13C]3-OHB reached a plateau 6–7 h after the start of the infusion in women but was still increasing at 6 h in men. This implies a slower 3-OHB production rate and/or dilution by other precursor pools in men. In women, the high isotopic enrichment of plasma 3-OHB suggested that systemic plasma fatty acids were the major source of 3-OHB production. However, in men, this was not observed during the course of the study (P < 0·01). There were no sex differences for the incorporation of13C into VLDL1- or VLDL2-TAG. The ability of young women to partition fatty acids towards ketone body production rather than VLDL-TAG may contribute to their more advantageous metabolic profile compared with young men.

scholarly journals Time course of ketone body production in the isolated perfused rat liver in response to various stimuli.

1986 ◽  
Vol 33 (6) ◽  
pp. 827-834 ◽  
Author(s):  
YUKICHI OKUDA ◽  
KOICHI KAWAI ◽  
YOSHINOBU KOIDE ◽  
KAMEJIRO YAMASHITA
Keyword(s):  
Rat Liver ◽  
Time Course ◽  
Ketone Body ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver ◽  
Body Production
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