Role of Leucine in the Regulation of Protein Metabolism

• Published in: The Journal of nutrition Vol. 135; no. 6S; pp. 1553 - 1556
• Main Author: Garlick, Peter J
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Bethesda, MD American Society for Nutritional Sciences 01.06.2005
• Subjects: Amino Acids, Branched-Chain - metabolism; Amino Acids, Branched-Chain - physiology; Animals; Biological and medical sciences; Dose-Response Relationship, Drug; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Glucose - metabolism; Humans; Insulin - blood; Insulin - metabolism; Insulin Secretion; leucine; Leucine - pharmacology; Leucine - physiology; literature reviews; liver; mechanism of action; Muscle Proteins - biosynthesis; Muscle Proteins - metabolism; Muscle, Skeletal - drug effects; Muscle, Skeletal - metabolism; nutrient intake; protein degradation; protein metabolism; protein synthesis; Rats; signal transduction; skeletal muscle; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Pancreatic hormone; Nutrition; Leucine; Metabolism; branched-chain amino acids; Insulin; Protein; Branched chain; Regulation(control); Protein synthesis; Valine; Aminoacid; Muscle; Isoleucine
• ISSN: 0022-3166; 1541-6100
• DOI: 10.1093/jn/135.6.1553s

Studies both in vivo and in vitro have shown that leucine at a very high dose can stimulate muscle protein synthesis, an effect that is enhanced in vivo by insulin secreted in response to the leucine dose. High leucine can also inhibit protein degradation in skeletal muscle, as well as in liver. In contrast, at normal physiological levels, increasing leucine concentration by infusion stimulates muscle protein synthesis by enhancing its sensitivity to insulin. It is concluded that the role of leucine in vivo is to provide a signal that amino acids are available, which in combination with the signal of energy availability from insulin, stimulates muscle protein synthesis.