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| ==What are Branched-Chain Amino Acids?== | | ==What are Branched-Chain Amino Acids?== |
− | The branched-chain amino acids (i.e., leucine, isoleucine and valine) are '''essential dietary amino acids for dogs and cats'''. Leucine is ketogenic; valine is gluconeogenic; and isoleucine is both ketogenic and gluconeogenic. Dietary branched-chain amino acids are absorbed by a neutral amino acid transporter in the small intestine (particularly the jejunum) and plasma branched-chain amino acids are actively reabsorbed in the proximal tubule of the kidney. | + | The branched-chain [[Amino Acids Overview - Nutrition|amino acids]] (i.e. leucine, isoleucine and valine) are '''essential dietary amino acids for dogs and cats'''. Leucine is [[Amino Acids Overview - Nutrition|ketogenic]]; valine is [[Amino Acids Overview - Nutrition|gluconeogenic]]; and isoleucine is both ketogenic and gluconeogenic. Dietary branched-chain amino acids are absorbed by a neutral amino acid transporter in the [[Small Intestine Overview - Anatomy & Physiology|small intestine]] (particularly the [[Jejunum - Anatomy & Physiology|jejunum]]) and plasma branched-chain amino acids are actively reabsorbed in the [[Nephron Microscopic Anatomy#Proximal Tubule|proximal tubule]] of the kidney. |
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| ==Why are they Important?== | | ==Why are they Important?== |
− | Branched-chain amino acids are '''structural components of protein'''. The hydrophobic side chains of branched-chain amino acids induce inward folding of protein structures. | + | Branched-chain amino acids are '''structural components of [[Protein Overview - Nutrition|protein]]'''. The hydrophobic side chains of branched-chain amino acids induce inward folding of protein structures. |
− | Severe liver disease may result in decreased plasma branched-chain amino acid concentrations relative to aromatic amino acids, and this is thought to play a role in the clinical signs of hepatic encephalopathy<ref>Strombeck DR and Rogers Q. Plasma amino acid concentrations in dogs with hepatic disease. JAVMA 1978; 178;93-96.</ref><ref>Meyer HP, et al. Effects of a branched-chain amino acid-enriched diet on chronic hepatic encephalopathy in dogs. Metab Br Dis 1999;14:103-110.</ref>. However, the clinical impact of attempting to alter amino acid balance favouring branched-chain amino acids in animals with hepatic encephalopathy is unknown. | + | Severe liver disease may result in decreased plasma branched-chain amino acid concentrations relative to [[Nutrition Glossary#Aromatic Amino Acids|aromatic amino acids]], and this is thought to play a role in the clinical signs of [[Hepatic Encephalopathy|hepatic encephalopathy]]<ref>Strombeck DR and Rogers Q. Plasma amino acid concentrations in dogs with hepatic disease. JAVMA 1978; 178;93-96.</ref><ref>Meyer HP, et al. Effects of a branched-chain amino acid-enriched diet on chronic hepatic encephalopathy in dogs. Metab Br Dis 1999;14:103-110.</ref>. However, the clinical impact of attempting to alter amino acid balance favouring branched-chain amino acids in animals with hepatic encephalopathy is unknown. |
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| ==Roles in the Body== | | ==Roles in the Body== |
− | Isoleucine, leucine and valine are constituents of protein. Leucine is also a key catabolic regulator of l branched-chain amino acids<ref name="Harris">Harris RA, et al. Regulation of branched-chain α-keto acid dehydrogenase kinase expression in rat liver. J Nutr 2001;131:841S-845S.</ref>. Leucine also influences protein synthesis and muscle deposition by increasing plasma insulin secretion<ref>Yang J, et al. Leucine metabolism in regulation of insulin secretion from pancreatic beta cells. Nutr Rev 2010;68:270-279.</ref>, sensitivity of insulin binding to muscle cells<ref>Prod’homme M, et al. Insulin and amino acids both strongly participate to the regulation of protein metabolism. Curr Opin Clin Nutr Met Car 2004;7:71-7.</ref><ref>Anthony JC, et al. Contribution of insulin to the translational control of protein synthesis in skeletal muscle by leucine. Am J Physiol Endo Metab 2002;282:E1092-E1101.</ref><ref>Liu H, et al. Leucine facilitates the insulin-stimulated glucose uptake and insulin signalling in skeletal muscle cells: involving mTORC1 and mTORC2. Amino Acids 2014;46:1971-1979.</ref>, and inhibiting muscle catabolism<ref>Nagasawa T, et al. Rapid suppression of protein degradation in skeletal muscle after oral feeding of leucine in rats. J Nutr Biochem 2002;13:121-127.</ref><ref>Kadowaki M and Kanazawa T. Amino Acids as Regulators of Proteolysis. J Nutr 2003;133:2052S-2056S.</ref>. | + | Isoleucine, leucine and valine are constituents of [[Protein Overview - Nutrition|protein]]. Leucine is also a key catabolic regulator of l branched-chain amino acids<ref name="Harris">Harris RA, et al. Regulation of branched-chain α-keto acid dehydrogenase kinase expression in rat liver. J Nutr 2001;131:841S-845S.</ref>. Leucine also influences protein synthesis and muscle deposition by increasing plasma [[insulin]] secretion<ref>Yang J, et al. Leucine metabolism in regulation of insulin secretion from pancreatic beta cells. Nutr Rev 2010;68:270-279.</ref>, sensitivity of insulin binding to muscle cells<ref>Prod’homme M, et al. Insulin and amino acids both strongly participate to the regulation of protein metabolism. Curr Opin Clin Nutr Met Car 2004;7:71-7.</ref><ref>Anthony JC, et al. Contribution of insulin to the translational control of protein synthesis in skeletal muscle by leucine. Am J Physiol Endo Metab 2002;282:E1092-E1101.</ref><ref>Liu H, et al. Leucine facilitates the insulin-stimulated glucose uptake and insulin signalling in skeletal muscle cells: involving mTORC1 and mTORC2. Amino Acids 2014;46:1971-1979.</ref>, and inhibiting muscle catabolism<ref>Nagasawa T, et al. Rapid suppression of protein degradation in skeletal muscle after oral feeding of leucine in rats. J Nutr Biochem 2002;13:121-127.</ref><ref>Kadowaki M and Kanazawa T. Amino Acids as Regulators of Proteolysis. J Nutr 2003;133:2052S-2056S.</ref>. |
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| ==Consequences of Branched-Chain Amino Acid Deficiency== | | ==Consequences of Branched-Chain Amino Acid Deficiency== |
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| ==Dietary Sources== | | ==Dietary Sources== |
− | Sufficient leucine, isoleucine, and valine are found in plant and animal protein sources, such as muscle meat, eggs, dairy protein (i.e., casein), cereal grains, and pulses (i.e., legumes). | + | Sufficient leucine, isoleucine, and valine are found in plant and animal protein sources, such as muscle meat, eggs, dairy protein (i.e. casein), cereal grains, and pulses (i.e. legumes). |
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| ==Diagnosing Branched-Chain Amino Acid Deficiency== | | ==Diagnosing Branched-Chain Amino Acid Deficiency== |
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| <references/> | | <references/> |
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− | [[Category:To Do - Nutrition]] | + | <br> |
| + | {{Reviewed Nutrition 1 |
| + | |date = 18 May 2015}} |
| + | {{Waltham}} |
| + | {{OpenPages}} |
| + | |
| + | [[Category:Amino Acids]] |