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John T Brosnan - One of the best experts on this subject based on the ideXlab platform.
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creatine and guanidinoacetate content of human milk and infant formulas implications for creatine deficiency syndromes and Amino Acid Metabolism
British Journal of Nutrition, 2013Co-Authors: Erica E Edison, Margaret E Brosnan, Khalid Aziz, John T BrosnanAbstract:Creatine is essential for normal neural development; children with inborn errors of creatine synthesis or transport exhibit neurological symptoms such as mental retardation, speech delay and epilepsy. Creatine accretion may occur through dietary intake or de novo creatine synthesis. The objective of the present study was to determine how much creatine an infant must synthesise de novo . We have calculated how much creatine an infant needs to account for urinary creatinine excretion (creatine's breakdown product) and new muscle lay-down. To measure an infant's dietary creatine intake, we measured creatine in mother's milk and in various commercially available infant formulas. Knowing the amount of milk/formula ingested, we calculated the amount of creatine ingested. We have found that a breast-fed infant receives about 9 % of the creatine needed in the diet and that infants fed cows' milk-based formula receive up to 36 % of the creatine needed. However, infants fed a soya-based infant formula receive negligible dietary creatine and must rely solely on de novo creatine synthesis. This is the first time that it has been shown that neonatal creatine accretion is largely due to de novo synthesis and not through dietary intake of creatine. This has important implications both for infants suffering from creatine deficiency syndromes and for neonatal Amino Acid Metabolism.
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Amino Acid Metabolism in the zucker diabetic fatty rat effects of insulin resistance and of type 2 diabetes
Canadian Journal of Physiology and Pharmacology, 2004Co-Authors: Enoka P Wijekoon, Craig Skinner, Margaret E Brosnan, John T BrosnanAbstract:We investigated Amino Acid Metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino Acids were measured ...
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Amino Acid Metabolism in the zucker diabetic fatty rat effects of insulin resistance and of type 2 diabetes
Canadian Journal of Physiology and Pharmacology, 2004Co-Authors: Enoka P Wijekoon, Craig Skinner, Margaret E Brosnan, John T BrosnanAbstract:We investigated Amino Acid Metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino Acids were measured in plasma, liver, and skeletal muscle, and the ratios of plasma/liver and plasma/skeletal muscle were calculated. At the insulin-resistant stage, the plasma concentrations of the gluconeogenic Amino Acids aspartate, serine, glutamine, glycine, and histidine were decreased in the ZDF Gmi fa/fa rats, whereas taurine, alpha-Aminoadipic Acid, methionine, phenylalanine, tryptophan, and the 3 branched-chain Amino Acids were significantly increased. At the diabetic stage, a larger number of gluconeogenic Amino Acids had decreased plasma concentrations. The 3 branched-chain Amino Acids had elevated plasma concentrations. In the liver and the skeletal muscles, concentrations of many of the gluconeogenic Amino Acids were lower at both stages, whereas the levels of 1 or all of the branched-chain Amino Acids were elevated. These changes in Amino Acid concentrations are similar to changes seen in type 1 diabetes. It is evident that insulin resistance alone is capable of bringing about many of the changes in Amino Acid Metabolism observed in type 2 diabetes.
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Amino Acid Metabolism in the zucker diabetic fatty rat effects of insulin resistance and of type 2 diabetes
Canadian Journal of Physiology and Pharmacology, 2004Co-Authors: Enoka P Wijekoon, Craig Skinner, Margaret E Brosnan, John T BrosnanAbstract:We investigated Amino Acid Metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino Acids were measured in plasma, liver, and skeletal muscle, and the ratios of plasma/liver and plasma/skeletal muscle were calculated. At the insulin-resistant stage, the plasma concentrations of the gluconeogenic Amino Acids aspartate, serine, glutamine, glycine, and histidine were decreased in the ZDF Gmi fa/fa rats, whereas taurine, α-Aminoadipic Acid, methionine, phenylalanine, tryptophan, and the 3 branched-chain Amino Acids were significantly increased. At the diabetic stage, a larger number of gluconeogenic Amino Acids had decreased plasma concentrations. The 3 branched-chain Amino Acids had elevated plasma concentrations. In the liver and the skeletal muscles, concentrations of many of the gluconeogenic Amino Acids were lower at both stages, whereas the levels of 1 or all of the branched-chain Amino Acids were elevated. Thes...
Margaret E Brosnan - One of the best experts on this subject based on the ideXlab platform.
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creatine and guanidinoacetate content of human milk and infant formulas implications for creatine deficiency syndromes and Amino Acid Metabolism
British Journal of Nutrition, 2013Co-Authors: Erica E Edison, Margaret E Brosnan, Khalid Aziz, John T BrosnanAbstract:Creatine is essential for normal neural development; children with inborn errors of creatine synthesis or transport exhibit neurological symptoms such as mental retardation, speech delay and epilepsy. Creatine accretion may occur through dietary intake or de novo creatine synthesis. The objective of the present study was to determine how much creatine an infant must synthesise de novo . We have calculated how much creatine an infant needs to account for urinary creatinine excretion (creatine's breakdown product) and new muscle lay-down. To measure an infant's dietary creatine intake, we measured creatine in mother's milk and in various commercially available infant formulas. Knowing the amount of milk/formula ingested, we calculated the amount of creatine ingested. We have found that a breast-fed infant receives about 9 % of the creatine needed in the diet and that infants fed cows' milk-based formula receive up to 36 % of the creatine needed. However, infants fed a soya-based infant formula receive negligible dietary creatine and must rely solely on de novo creatine synthesis. This is the first time that it has been shown that neonatal creatine accretion is largely due to de novo synthesis and not through dietary intake of creatine. This has important implications both for infants suffering from creatine deficiency syndromes and for neonatal Amino Acid Metabolism.
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Amino Acid Metabolism in the zucker diabetic fatty rat effects of insulin resistance and of type 2 diabetes
Canadian Journal of Physiology and Pharmacology, 2004Co-Authors: Enoka P Wijekoon, Craig Skinner, Margaret E Brosnan, John T BrosnanAbstract:We investigated Amino Acid Metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino Acids were measured ...
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Amino Acid Metabolism in the zucker diabetic fatty rat effects of insulin resistance and of type 2 diabetes
Canadian Journal of Physiology and Pharmacology, 2004Co-Authors: Enoka P Wijekoon, Craig Skinner, Margaret E Brosnan, John T BrosnanAbstract:We investigated Amino Acid Metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino Acids were measured in plasma, liver, and skeletal muscle, and the ratios of plasma/liver and plasma/skeletal muscle were calculated. At the insulin-resistant stage, the plasma concentrations of the gluconeogenic Amino Acids aspartate, serine, glutamine, glycine, and histidine were decreased in the ZDF Gmi fa/fa rats, whereas taurine, alpha-Aminoadipic Acid, methionine, phenylalanine, tryptophan, and the 3 branched-chain Amino Acids were significantly increased. At the diabetic stage, a larger number of gluconeogenic Amino Acids had decreased plasma concentrations. The 3 branched-chain Amino Acids had elevated plasma concentrations. In the liver and the skeletal muscles, concentrations of many of the gluconeogenic Amino Acids were lower at both stages, whereas the levels of 1 or all of the branched-chain Amino Acids were elevated. These changes in Amino Acid concentrations are similar to changes seen in type 1 diabetes. It is evident that insulin resistance alone is capable of bringing about many of the changes in Amino Acid Metabolism observed in type 2 diabetes.
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Amino Acid Metabolism in the zucker diabetic fatty rat effects of insulin resistance and of type 2 diabetes
Canadian Journal of Physiology and Pharmacology, 2004Co-Authors: Enoka P Wijekoon, Craig Skinner, Margaret E Brosnan, John T BrosnanAbstract:We investigated Amino Acid Metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino Acids were measured in plasma, liver, and skeletal muscle, and the ratios of plasma/liver and plasma/skeletal muscle were calculated. At the insulin-resistant stage, the plasma concentrations of the gluconeogenic Amino Acids aspartate, serine, glutamine, glycine, and histidine were decreased in the ZDF Gmi fa/fa rats, whereas taurine, α-Aminoadipic Acid, methionine, phenylalanine, tryptophan, and the 3 branched-chain Amino Acids were significantly increased. At the diabetic stage, a larger number of gluconeogenic Amino Acids had decreased plasma concentrations. The 3 branched-chain Amino Acids had elevated plasma concentrations. In the liver and the skeletal muscles, concentrations of many of the gluconeogenic Amino Acids were lower at both stages, whereas the levels of 1 or all of the branched-chain Amino Acids were elevated. Thes...
Paul B Pencharz - One of the best experts on this subject based on the ideXlab platform.
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sulfur Amino Acid Metabolism and requirements
Nutrition Reviews, 2012Co-Authors: Glenda Courtneymartin, Ronald O Ball, Paul B PencharzAbstract:The sulfur Amino Acids (SAA) are methionine and cysteine. Methionine is indispensable.1–5 It donates its sulfur atom to cysteine during the process of trans-sulfuration, making cysteine a dispensable Amino Acid.6 The carbon skeleton of cysteine, however, is donated by serine.6 Methionine is metabolized via three major metabolic pathways: transmethylation, remethylation, and trans-sulfuration. It serves as the major methyl group donor in vivo,7,8 while cysteine is the rate-limiting substrate for the synthesis of the antioxidant glutathione (GSH).9–11 Both Amino Acids are important for protein synthesis. The total sulfur Amino Acid (TSAA) requirement, when fulfilled by the provision of methionine, can be significantly reduced only by adding cysteine to the diet. This phenomenon has been firmly established in animals12–15 and in humans16–18; it is consistent across the lifespan, having been observed in neonates,5–20 children,21 and adults.17,18 In the present issue of this journal, F. Jahoor examines the role the availability of sulfur Amino Acids plays in severe childhood undernutrition.22 The present editorial complements that work by providing an overview of SAA Metabolism and requirements. ### Methionine In healthy adults, the Metabolism of methionine is regulated toward anabolism23 in the fed state, and methionine flux is increased relative to that observed in the fasted state. Feeding results in decreased methionine release from protein breakdown and increased transmethylation, trans-sulfuration, and remethylation. In the fasted state, methionine utilization for protein synthesis is increased relative to transmethylation, resulting in the conservation of methionine when SAA availability is low. When SAAs are absent from the diet of healthy adults,17 methionine is used preferentially for protein synthesis relative to transmethylation, confirming previous findings that methionine is conserved via protein synthesis when SAA …
Nathan J Cherrington - One of the best experts on this subject based on the ideXlab platform.
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branched chain Amino Acid Metabolism profiles in progressive human nonalcoholic fatty liver disease
Amino Acids, 2015Co-Authors: April D Lake, Petr Novak, Petia Shipkova, Nelly Aranibar, Donald G Robertson, Michael D Reily, Lois D Lehmanmckeeman, Richard R Vaillancourt, Nathan J CherringtonAbstract:Nonalcoholic fatty liver disease (NAFLD) is a globally widespread disease of increasing clinical significance. The pathological progression of the disease from simple steatosis to nonalcoholic steatohepatitis (NASH) has been well defined, however, the contribution of altered branched chain Amino Acid metabolomic profiles to the progression of NAFLD is not known. The three BCAAs: leucine, isoleucine and valine are known to mediate activation of several important hepatic metabolic signaling pathways ranging from insulin signaling to glucose regulation. The purpose of this study is to profile changes in hepatic BCAA metabolite levels with transcriptomic changes in the progression of human NAFLD to discover novel mechanisms of disease progression. Metabolomic and transcriptomic data sets representing the spectrum of human NAFLD (normal, steatosis, NASH fatty, and NASH not fatty livers) were utilized for this study. During the transition from steatosis to NASH, increases in the levels of leucine (127 % of normal), isoleucine (139 %), and valine (147 %) were observed. Carnitine metabolites also exhibited significantly elevated profiles in NASH fatty and NASH not fatty samples and included propionyl, hexanoyl, lauryl, acetyl and butyryl carnitine. Amino Acid and BCAA Metabolism gene sets were significantly enriched among downregulated genes during NASH. These cumulative alterations in BCAA metabolite and Amino Acid Metabolism gene profiles represent adaptive physiological responses to disease-induced hepatic stress in NASH patients.
Enoka P Wijekoon - One of the best experts on this subject based on the ideXlab platform.
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Amino Acid Metabolism in the zucker diabetic fatty rat effects of insulin resistance and of type 2 diabetes
Canadian Journal of Physiology and Pharmacology, 2004Co-Authors: Enoka P Wijekoon, Craig Skinner, Margaret E Brosnan, John T BrosnanAbstract:We investigated Amino Acid Metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino Acids were measured ...
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Amino Acid Metabolism in the zucker diabetic fatty rat effects of insulin resistance and of type 2 diabetes
Canadian Journal of Physiology and Pharmacology, 2004Co-Authors: Enoka P Wijekoon, Craig Skinner, Margaret E Brosnan, John T BrosnanAbstract:We investigated Amino Acid Metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino Acids were measured in plasma, liver, and skeletal muscle, and the ratios of plasma/liver and plasma/skeletal muscle were calculated. At the insulin-resistant stage, the plasma concentrations of the gluconeogenic Amino Acids aspartate, serine, glutamine, glycine, and histidine were decreased in the ZDF Gmi fa/fa rats, whereas taurine, alpha-Aminoadipic Acid, methionine, phenylalanine, tryptophan, and the 3 branched-chain Amino Acids were significantly increased. At the diabetic stage, a larger number of gluconeogenic Amino Acids had decreased plasma concentrations. The 3 branched-chain Amino Acids had elevated plasma concentrations. In the liver and the skeletal muscles, concentrations of many of the gluconeogenic Amino Acids were lower at both stages, whereas the levels of 1 or all of the branched-chain Amino Acids were elevated. These changes in Amino Acid concentrations are similar to changes seen in type 1 diabetes. It is evident that insulin resistance alone is capable of bringing about many of the changes in Amino Acid Metabolism observed in type 2 diabetes.
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Amino Acid Metabolism in the zucker diabetic fatty rat effects of insulin resistance and of type 2 diabetes
Canadian Journal of Physiology and Pharmacology, 2004Co-Authors: Enoka P Wijekoon, Craig Skinner, Margaret E Brosnan, John T BrosnanAbstract:We investigated Amino Acid Metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino Acids were measured in plasma, liver, and skeletal muscle, and the ratios of plasma/liver and plasma/skeletal muscle were calculated. At the insulin-resistant stage, the plasma concentrations of the gluconeogenic Amino Acids aspartate, serine, glutamine, glycine, and histidine were decreased in the ZDF Gmi fa/fa rats, whereas taurine, α-Aminoadipic Acid, methionine, phenylalanine, tryptophan, and the 3 branched-chain Amino Acids were significantly increased. At the diabetic stage, a larger number of gluconeogenic Amino Acids had decreased plasma concentrations. The 3 branched-chain Amino Acids had elevated plasma concentrations. In the liver and the skeletal muscles, concentrations of many of the gluconeogenic Amino Acids were lower at both stages, whereas the levels of 1 or all of the branched-chain Amino Acids were elevated. Thes...