Creatine synthesis and methionine partitioning during TPN in Yucatan miniature piglets

Bray, Scott D. (2017) Creatine synthesis and methionine partitioning during TPN in Yucatan miniature piglets. Masters thesis, Memorial University of Newfoundland.

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Abstract

Methionine is an indispensable amino acid in the diet of neonates and has a metabolic role in the synthesis of creatine, phosphatidylcholine (PC) as well as protein synthesis and other transmethylation reactions. Creatine synthesis consumes significant amounts of arginine (a conditionally essential amino acid) and methionine, while PC requires methionine for its synthesis. Total parenteral nutrition (TPN) is typically marginal in these amino acids, and devoid in creatine. Therefore, our objective was to quantify the partitioning of methyl groups among transmethylation reactions and the sparing effect of dietary creatine and GAA on protein synthesis. Adequate supply of dietary methionine resulted in significantly greater hepatic fractional synthesis rate (FSR) of PC. Furthermore, GAA supplementation increased FSR of creatine by approximately 175%, but only when adequate dietary methionine was supplied. Moreover, piglet weight gain was similar to that of piglets receiving adequate arginine, suggesting arginine was spared for growth. Overall, supplemental GAA could be considered as a novel TPN ingredient to increase the synthesis of creatine and spare arginine for growth, but only when adequate methionine is provided.

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