Further studies on the entry rates of acetate and glucose in sheep, with special reference to endogenous production of acetate

Annison, E. F.; White, R. R.

doi:10.1042/bj0840546

Cited by 59 publications

(8 citation statements)

References 9 publications

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“…Vacuum transfer has the added advantage that it concentrates the sample and thus reduces the volumes of blood required. Initially, as an internal standard, we used isobutyric acid (27), but found that its concentration fell off rapidly on standing in orthophosphoric acid solution, due probably to micellar separation (27,32 (21,(35)(36)(37)(38)(39). In normal fasting animals, for instance, circulating blood acetate is mainly endogenous (liver) in origin in contrast to the fed state, as in the present study, where the gut is the major source (38,39).…”

Section: Discussionmentioning

confidence: 53%

Carbohydrate fermentation in the human colon and its relation to acetate concentrations in venous blood.

Pomare¹,

Branch²,

Cummings³

1985

J. Clin. Invest.

283

118

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There is now substantial evidence that some dietary polysaccharides, notably dietary fiber, escape absorption in the small bowel and are then broken down in the large intestine of man. The main end products of this colonic digestive process, which is anerobic, are short chain fatty acids (SCFA), and acetic, propionic, and butyric acids. Although these acids are known to be absorbed from the colon, their subsequent fate and significance is unknown. We have measured venous blood SCFA levels in healthy subjects after a 16-h fast, and then following oral doses of either 50 mmol SCFA,5,10, or liter. Pectin fermentation was much slower, with blood acetate levels starting to rise after 6 h and remaining elevated at about twice fasting levels for the subsequent 18 h. However, areas under the blood acetate curves were closely related (r = 0.97; n = 5), whatever the source of acetate. These studies show that the large intestine makes an important contribution to blood acetate levels in man and that fermentation may influence metabolic processes well beyond the wall of this organ.

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Section: Discussionmentioning

confidence: 53%

Carbohydrate fermentation in the human colon and its relation to acetate concentrations in venous blood.

Pomare¹,

Branch²,

Cummings³

1985

J. Clin. Invest.

283

118

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“…The pump was supplied by a reservoir kept filled from a carotid artery using a magnetic clamp controlled by the blood level. The specific activity of glucose was determined by recrystallizing glucose pentaacetate as described by Jones (1965), that of acetate after steam distillation as described by Annison & White (1962) and that of carbon dioxide by the method of Hinks, Mills & Setchell (1966) or Annison & Lindsay (1961).…”

Section: Sheep and Goat Testis Perfusion 131mentioning

confidence: 99%

Metabolism, sperm and fluid production of the isolated perfused testis of the sheep and goat

Linzell¹,

Setchell²

1969

The Journal of Physiology

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SUMMARY1. A total of nineteen ram and three goat testes have been perfused in isolation at 34-35°C for 3j-9 hr with heparinized blood and an added 5-HT antagonist (bromolysergic acid diethylamide) and their function compared with that of the normal ram testes in vtvo.2. The metabolism of the perfused testes and the testes in vivo was similar but blood flow through the perfused testes was two to three times normal.3. Vasoconstriction was produced by adrenaline and noradrenaline (10-20 /tg I.A.) and by electrical stimulation of nerves in the spermatic cord or of the lumbar sympathetic chain; these responses were abolished or reduced by phenoxybenzamine. 4. Flow of fluid from the rete testis continued only if ischaemia was reduced to a minimum and glucose concentration in the blood perfusing the testis was kept above about 25 mg/100 ml.; the fluid secreted during perfusion was of normal composition.5. The perfused testis showed no evidence of autoregulation and the flow of fluid was not affected by changes in perfusion pressure.6. When the temperature of three testes was raised to 40°C for 2 hr, metabolism increased but blood flow was unaltered; the flow of fluid and the concentration of spermatozoa decreased during heating.7. The testes perfused at normal scrotal temperatures (34-35' C) were histologically normal but some abnormalities were observed in the heated testes.

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“…This suggested the production of considerable amounts of endogenous acetate, a ®nding con®rmed by isotope dilution studies which showed that in sheep about 25 % of total acetate turnover is of non-alimentary origin (Annison & White, 1962b;Bergman & Wolff, 1971;Costa et al 1976). …”

Section: Short-chain Fatty Acid Metabolismmentioning

confidence: 91%

Perspectives on ruminant nutrition and metabolism. II. Metabolism in ruminant tissues

Annison

Bryden

1999

Nutr. Res. Rev.

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The discovery of the dominance of short-chain fatty acids as energy sources in the 1940s and 1950s, as discussed in part I of this review (Annison & Bryden, 1998) led to uncertainties concerning the interrelationships of glucose and acetate in ruminant metabolism. These were resolved in the following decade largely by use of 14 C-labelled substrates. Although only small amounts of glucose are absorbed in most dietary situations, glucose availability to ruminant tissues as measured by isotope dilution was shown to be substantial, indicating that gluconeogenesis is a major metabolic activity in both fed and fasted states. Studies with 14 C-labelled glucose and acetate revealed that in contrast to non-ruminants, acetate and not glucose is the major precursor of long-chain fatty acids in ruminant tissues. Interest in the measurement of energy metabolism in livestock grew rapidly from the 1950s. Most laboratories adopted indirect calorimetry and precise measurements of the energy expenditure of ruminants contributed to the development of new feeding systems. More recently, alternative approaches to the measurement of energy expenditure have included the use of NMR spectroscopy, isotope dilution and the application of the Fick principle to measure O 2 consumption in the whole animal and in de®ned tissues. The re®nement of the classical arterio-venous difference procedure in the study of mammary gland metabolism in the 1960s, particularly when combined with isotope dilution, encouraged the use of these methods to generate quantitative data on the metabolism of a range of de®ned tissues. The recent introduction of new methods for the continuous monitoring of both blood¯ow and blood O 2 content has greatly increased the precision and scope of arterio-venous difference measurements. The impact of data produced by these and other quantitative procedures on current knowledge of the metabolism of glucose, short-chain fatty acids and lipids, and on N metabolism, is outlined. The role of the portal-drained viscera and liver in N metabolism is discussed in relation to data obtained by the use of multi-catheterized animals. Protein turnover, and the impact of stress (physical, social and disease related) on protein metabolism have been reviewed. The growth of knowledge of mammary gland metabolism and milk synthesis since the ®rst quantitative studies in the 1960s has been charted. Recent ®ndings on the regulation of amino acid uptake and utilization by the mammary gland, and on the control of milk secretion, are of particular interest and importance.

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Further studies on the entry rates of acetate and glucose in sheep, with special reference to endogenous production of acetate

Cited by 59 publications

References 9 publications

Carbohydrate fermentation in the human colon and its relation to acetate concentrations in venous blood.

Carbohydrate fermentation in the human colon and its relation to acetate concentrations in venous blood.

Metabolism, sperm and fluid production of the isolated perfused testis of the sheep and goat

Perspectives on ruminant nutrition and metabolism. II. Metabolism in ruminant tissues

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