Why insulin is key for intracellular protein synthesis

When you’ve just eaten some protein, insulin, glucagon, growth hormone and glucocorticoids increase because of the presence of elevated amino acid concentration (1p232). The insulin promotes the protein synthesis and the other hormones have an opposite effect (1p232). Growth hormone is anabolic like insulin, although counterregulatory (1p232). Insulin to glucagon ratio favoring insulin stimulates protein synthesis enzymes and vice versa (1p232). The insulin is needed for uptake of amino acids across the cell membrane and antagonizing activation of amino acid oxidation by some enzymes (1p206-207).

Protein synthesis is also sensitive to multiple influences including stability of mRNA, amount of rRNA, activity of ribosomes, and (most important from diet), the presence of essential and nonessential amino acids in appropriate concentration to charge the tRNA and hormone environment (1p232). When amino acids are not present or not present in sufficient quantity, amino acid oxidation increases (1p232).

Reference List

1. Gropper SS, Smith JL, Groff JL. Advanced Nutrition and Human Metabolism. Belmont, CA: Thomson Wadsworth, 2009.

Published by David Despain, MS, CFS

David is a science and health writer living on Long Island, New York. He's written for a variety of publications including Scientific American, Outside Online, the American Society for Nutrition's (ASN) Nutrition Notes Daily, and Institute of Food Technologists' (IFT) Food Technology magazine and Live! blog. He's also covered new findings reported at scientific meetings including Experimental Biology, AAAS, AOCS, CASW, Sigma Xi, IFT, and others on his personal blog "Evolving Health." David is also an active member of organizations including the National Association of Science Writers (NASW), the American Association for the Advancement of Science (AAAS), the American Society for Nutrition, the Institute of Food Technologists, and the National Audubon Society. David has a master's degree in human nutrition from the University of Bridgeport, and a bachelor's degree in English from University of Illinois at Springfield. He also earned his Certified Food Scientist credential from the Institute of Food Technologists.

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