Conversion of Fatty Acids to Carbohydrate: Application of Isotopes to this Problem and Role of the Krebs Cycle as a Synthetic Pathway

Weinman, E. O.; Strisower, E. H.; Chaikoff, I.L.

doi:10.1152/physrev.1957.37.2.252

Cited by 178 publications

(79 citation statements)

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“…The results of the present studies confirm previous findings that two major pathways are involved in the formation of rumen volatile fatty acids (Jayasuriya & Hungate, 1959;Van Campen & Matrone, 1960;Baldwin, Wood & Emery, 1962 (Weinman, Strisower & Chaikoff, 1957), although some propionic acid carbon could be transferred to acetic acid via the glyoxalate pathway or acrylate pathway (Baldwin et al 1962 Gray et al (1960) observed that interconversions between acids had occurred and their calculated production rates could only be considered as gross entry rates. In the present study, the mean net production rates of volatile fatty acids in the rumen were 3-7, 1-0 and 0-7moles/day for acetic acid, propionic acid and butyric acid respectively when the sheep were eating 900g.…”

Section: Discussionsupporting

confidence: 92%

Interconversions and production of volatile fatty acids in the sheep rumen

Bergman¹,

Reid²,

Murray³

et al. 1965

Biochemical Journal

135

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1. Sheep fed at a constant rate were infused intraruminally with [1-14C]-acetate, -propionate or -butyrate during 5hr. periods. 2. Volatile fatty acids were estimated in the rumen contents and steady-state conditions were obtained. 3. Of the butyric acid carbon 60% was in equilibrium with 20% of the acetic acid carbon, and 2-3g.atoms of carbon were interconverted/day. 4. Little interconversion took place between propionic acid, acetic acid or butyric acid. 5. The net production rates for acetic acid, propionic acid and butyric acid were 3 7, 1-0 and 0-7moles/day respectively. 6. The production of volatile fatty acids accounted for 80% of the animal's energy expenditure.

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Section: Discussionsupporting

confidence: 92%

Interconversions and production of volatile fatty acids in the sheep rumen

Bergman¹,

Reid²,

Murray³

et al. 1965

Biochemical Journal

135

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“…There are also differences in the specific activities of the non-lipid bacterial carbon formed from the two kinds of acetate. These distributions are consistent with the operation of a citric acid cycle that is performing synthetic finctions (Weinman, Strisower & Chaikoff, 1957).…”

Section: P8supporting

confidence: 74%

“…The isotope distributions in the 2-oxoglutaric and succinic acid formed in the presence of [1-14C]-and [2-14C]-acetate conform to the wellknown patterns of labelling which can be deduced from the theory of the citric acid cycle by application of principles enunciated by Strisower, Kohler & Chaikoff (1952) and Weinman et al (1957). These principles assume that acetate of constant specific activity enters the cycle at a constant rate.…”

Section: Fixation Of Carbon Dioxide By Mycobacterium Butyricumsupporting

confidence: 65%

The metabolism of glycerol in Mycobacterium butyricum

Edson

Hunter

Kulka

et al. 1959

Biochemical Journal

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“…According to the findings of Weinman et al [32] and Krebs et al 1331, one can assume that a large fraction of 14C from pyruvate can appear as 14C02 even though most of the pyruvate is serving as a substrate for glucose synthesis. The crossingover of carbon from gluconeogenic substrate to carbon dioxide is possible since oxaloacetate serves as a common intermediate both on the pathway to gluconeogenesis and in the tricarboxylic acid cycle…”

Section: Discussionmentioning

confidence: 99%

Effect of Oleic Acid on the Oxidation and Gluconeogenesis from [1‐¹⁴C]Pyruvate in the Perfused Rat Liver

Teufel¹,

Menahan²,

Shipp

et al. 1967

European Journal of Biochemistry

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Gluconeogenesis from [l-14C]pyruvate in the perfused liver from fasted rats was stimulated by oleic acid as indicated by an increase in medium glucose, liver glycogen and specific activity of medium [14C]glucose. A balance of carbon from pyruvate revealed that in the presence of oleic acid 2 moles of pyruvate were utilized for each mole of glucose synthesized in contrast to a ratio 4: 1 without fatty acid. From this and 14C0, data it is concluded that oleic acid inhibited pyruvate oxidation markedly. Glucagon increased glucose formation from pyruvate but not from glycerol.Tremendous interest in the factors controlling the rate of gluconeogenesis has been shown in recent years. Long-chain fatty acids have been found to stimulate gluconeogenesis in the perfused rat liver using lactate [l] or alanine as substrate [2,3], and caprylate stimulates glucose formation in liver slices [4]. Increased fatty acid oxidation and ketogenesis have also been implicated in the i n vivo stimulation of gluconeogenesis by glucagon [5,6]. This interrelationship between increased fatty acid oxidation and gluconeogenesis has pointed to an acetyl-CoA activation of pyruvic carboxylase [7] as one of the possible control points in gluconeogenesis [S]. Recently, caprylate [9] and palmitate [lo] have been observed to decrease the oxidation of pyruvate by rat liver mitochondria, which is possibly due to an inhibition of pyruvic dehydrogenase by acetylCoA [10,11].Although glucagon has been reported to stimulate glucose production from lactate [1,12,13], pyruvate [13], fructose [13], and glycerol [14], studies of hepatic intermediates [6,12] have indicated that glucagon may accelerate gluconeogenesis a t the ratelimiting level which exists between pyruvate and phosphoenolpyruvate.The present work is a continuation and extension of the studies on the control of gluconeogenesis initiated by Struck and co-workers in our laborato-' Y [151.These workers found a stimulation of gluconeogenesis from lactate by either glucagon or oleic acid. The present studies are concerned with gluconeogenesis from pyruvate and the effect of oleic acid on this rate. The effect of glucagon on gluconeogenesis from glycerol and pyruvate has also been investigated. MATERIALS AND METHODSMale albino rats (Sprague-Dawley, Gassner, Munchen), weighing between 180 and 250 g and previously fed on laboratory chow (Altromin R., Altrogge, Lage Lippe) were fasted for 18-20 h before use.All chemicals were reagent grade unless otherwise noted. L-lactic acid and DL-carnitine chloride were from Schuchardt (Munchen) and oleic acid from Riedel-DeHaen (Seelze-Hannover). The oleic acid was vacuum distilled prior to use. Glucagon was a preparation and a gift of Eli Lilly, Indianapolis, U.S.A. (Lot Nr. 258-234, B-167-1). Sodium [1-14C]-pyruvate was obtained from Radiochemical Center, Amersham, England. All substrates were prepared as neutral solutions. Glucagon was dissolved in 1/250 N HCI.The apparatus and technique of perfusion were similar to that previously described [16,17]. The perfusin...

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Conversion of Fatty Acids to Carbohydrate: Application of Isotopes to this Problem and Role of the Krebs Cycle as a Synthetic Pathway

Cited by 178 publications

References 0 publications

Interconversions and production of volatile fatty acids in the sheep rumen

Interconversions and production of volatile fatty acids in the sheep rumen

The metabolism of glycerol in Mycobacterium butyricum

Effect of Oleic Acid on the Oxidation and Gluconeogenesis from [1‐¹⁴C]Pyruvate in the Perfused Rat Liver

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Conversion of Fatty Acids to Carbohydrate: Application of Isotopes to this Problem and Role of the Krebs Cycle as a Synthetic Pathway

Cited by 178 publications

References 0 publications

Interconversions and production of volatile fatty acids in the sheep rumen

Interconversions and production of volatile fatty acids in the sheep rumen

The metabolism of glycerol in Mycobacterium butyricum

Effect of Oleic Acid on the Oxidation and Gluconeogenesis from [1‐14C]Pyruvate in the Perfused Rat Liver

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Product

Resources

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Effect of Oleic Acid on the Oxidation and Gluconeogenesis from [1‐¹⁴C]Pyruvate in the Perfused Rat Liver