Glutamine absorption

Lima AA, Carvalho GH, Figueiredo AA, Gi-foni AR, Soares AM, Silva EA, Guerrant RL Effects of an alanyl-glutamine-based oral rehydration and nutrition therapy solution on electrolyte and water absorption in a rat model of secretory diarrhea induced by cholera toxin. Nutrition 2002 18 458-462. 

The two important fuels for colonocytes are glutamine and short-chain fatty acids. The oxidation of both fuels provides ATP for the cells, which is important not only to maintain digestive and absorptive functions but also to maintain membrane structure and hence the physical barrier between the lumen and the blood and peritoneal cavity. This barrier normally prevents significant rates of translocation of bacteria into the peritoneal cavity and thence into the blood. If this barrier is breached, translocation of pathogens and... 

Although glutamine is present in protein and therefore made available in the lumen of the intestine by digestion, most of this is metabolised after absorption by the enterocytes in the intestine. Glutamine, therefore, has to be synthesised in the body, the precursors for which are glucose and branched-chain amino acids. It is synthesised in muscle, adipose tissue and the lung (see Figure 8.23). Furthermore, muscle... 

The amino acid substrates that are most recognized by Y-glulamyltranspeplidase are cysteine, glutamine, methioniney alanine, and serine. The products of the reaction, apparently, are efficiently transported into the epithelial cell, and then broken down into their constituent amino acids in the cell. The elucidation of the series of reactions involving formation of the y-glutamyl-amino acid, absorption of the products, hydrolysis of the products, and ro-formation of glutathione was mainly the work of Alton Meister (Meister, 1989). 

Hornsby-Lewis L, Shike M, Brown P, Klang M, Pearlstone D, Brennan MF. L-glutamine supplementation in home total parenteral nutrition patients stability, safety, and effects on intestinal absorption. J Parenter Enteral Nutr 1994 18(3) 268-73. 

Despite the lack of controlled clinical trials supporting its use, many clinicians supplement PN therapy with glutamine and recombinant growth hormone in an attempt to increase intestinal absorption and facilitate transition off PN. Recombinant growth hormone is a costly product with adverse effects, but PN is more costly and also has a serious adverse-effect pro-file. Larger controlled clinical trials are needed to determine the benefit of glutamine and rhGH in this patient population. 

Szkudlarek J, Jeppesen PB, Mortensen PB. Effect of high dose growth hormone with glutamine and no change in diet on intestinal absorption in short bowel patients A randomised, double blind, crossover, placebo controlled study. Gut 2000 47 199-205. 

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