Hormonal Control of Glucose Metabolism

Weekes, T. E. C.

doi:10.1016/b978-0-12-702290-1.50016-3

Cited by 34 publications

(19 citation statements)

References 57 publications

(51 reference statements)

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“…The present study was designed to quantify the effects of postruminal starch digestion on glucose and lactate metabolism in breeding ewes, thereby extending earlier work using adult wethers (Janes et al 1985) to physiological states with high glucose requirements (Weekes, 1991). Food intake was restricted in pregnancy to the same level as used Values are given as means + S.E.M.…”

Section: Discussionmentioning

confidence: 99%

“…Glucose turnover rates in ruminants are generally linearly related to energy intake (Oddy, Gooden, Hough, Teleni & Annison, 1985;Weekes, 1991). Fetal demands in late pregnancy have, however, been shown to increase glucose turnover relative to nonpregnant ewes fed at the same level, whereas in lactation dietary intake had a greater influence on glucose turnover (Wilson et al 1983).…”

Section: Discussionmentioning

confidence: 99%

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Glucose and L‐lactate metabolism in pregnant and in lactating ewes fed barley‐ or ground maize‐based diets

Perry¹,

Janes²,

Weekes³

et al. 1994

Experimental Physiology

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SUMMARYThe contribution of glucose absorbed from the small intestine to whole-body glucose metabolism was examined in ewes during late pregnancy and early lactation, using diets based on ground barley or ground maize. Glucose and L-lactate turnover in the whole body and the mesenteric-drained viscera were investigated in these ewes using isotope dilution techniques. The net absorption of glucose by the mesenteric-drained viscera and whole-body glucose turnover were unaffected by diet or reproductive status. Arterial and mesenteric venous blood glucose concentrations, arterial and mesenteric venous L-lactate concentrations and wholebody lactate turnover were all significantly higher in lactation than in pregnancy. The wholebody rates of lactate conversion to glucose and to other products were significantly higher in lactation than in pregnancy. Using a two-pool model of whole-body glucose and lactate metabolism, a relatively high percentage of glucose was converted to lactate (64-84%), accounting for 60-80% of whole-body lactate turnover. A model of glucose and lactate metabolism by the mesenteric-drained viscera was constructed. Both the calculated endogenous glucose production and the visceral conversion of glucose to lactate were greater in lactation than in pregnancy when barley was fed. Calculated total glucose absorption was relatively constant, contributing between 26 and 59% of whole-body glucose turnover. Diet had little effect on glucose and lactate metabolism in either the mesenteric-drained viscera or the wholebody of breeding ewes.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Glucose and L‐lactate metabolism in pregnant and in lactating ewes fed barley‐ or ground maize‐based diets

Perry¹,

Janes²,

Weekes³

et al. 1994

Experimental Physiology

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“…Assim, pequeno suprimento de glicose exógena estimula a rápida produção de insulina, que é o principal hormônio controlador da utilização de glicose pelos tecidos extra-hepáticos em ruminantes, apresentando ainda, ação no metabolismo de proteínas e lipídeos (Weeks, 1989).…”

Section: Carboidratosunclassified

Metabolismo De Carboidratos Não-Estruturais Em Ruminantes

Cañizares¹,

Rodrigues²,

Cañizares³

2009

AVS

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R RE ES SU UM MO OOs carboidratos constituem de 50 a 80% da matéria seca dos volumosos e grãos e podem ser divididos em estruturais (celulose, hemicelulose) e não-estruturais (amido, pectina e açúcares). Os carboidratos não-estruturais são digeridos principalmente no rúmen e seu processo é uma seqüência dinâmica para o fornecimento de nutrientes ao intestino. A qualidade e a quantidade de produtos resultantes da fermentação ruminal são dependentes do tipo e atividade dos microrganismos do rúmen influenciado pelo tipo de alimentação e processamento em que são submetidos os grãos de cereais que compõe a dieta. Os CNE escapam da fermentação ruminal para serem digeridos em glicose no intestino delgado pelas enzimas de origem pancreáticas (α-amilase) e mucosa intestinal (maltase e isomaltase). O amido é o maior componente fornecedor de energia dos grãos de cereais, os quais são importantes componentes das dietas utilizadas para as produções intensivas de leite e carne.Palavras-chave: amido, digestão de carboidratos, fermentação ruminal, glicose, pectina A AB BS ST TR RA AC CT TThe carbohydrates provide 50 to 80% of the dry matter of grain and roughage and can be divided into structural (cellulose, hemicellulose) and non-structural (starch, pectin and sugars). The non-structural carbohydrates are primarily digested in the rumen and its dynamic process is a sequence for the supply of nutrients to the intestine. The quality and quantity of products resulting from ruminal fermentation are dependent on the type and activity of microorganisms in the rumen influenced by the type of food processing and that are subject of cereal grains that make up the diet. The NSC escape of rumen fermentation to be digested into glucose in the small intestine by pancreatic enzymes of origin (α-amylase) and intestinal mucosa (maltase and isomaltase). Starch is the most important energy supplier of cereals, which are important components of diets for intensive production of milk and meat.Key words: carbohydrates digestion, glucose, pectin, ruminal fermentation, starch A Ar rt ti ig go o d de e R Re ev vi is sã ão o

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“…In addition, whole-body glucose entry was measured by isotope dilution. As expected, intestinal absorption of glucose was low on the dried-grass diet, but high on the ground-maize diet, and in the latter animals, endogenous glucose production was partially suppressed, as discussed by Weekes (1991).…”

Section: Gluconeogenesismentioning

confidence: 56%

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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Hormonal Control of Glucose Metabolism

Cited by 34 publications

References 57 publications

Glucose and L‐lactate metabolism in pregnant and in lactating ewes fed barley‐ or ground maize‐based diets

Glucose and L‐lactate metabolism in pregnant and in lactating ewes fed barley‐ or ground maize‐based diets

Metabolismo De Carboidratos Não-Estruturais Em Ruminantes

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

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