Glutamine: A New Metabolic Substrate
Glutamine serves important metabolic functions in a variety of tissues, but it has only recently been recognized as a new component of the metabolism of bone-Glutamine and glutamate are present as free amino acids in bone water at concentrations 2.5 and 40 times greater than their respective concentrations in plasma. The mediated transport of glutamine into calvaria occurs almost exclusively by Na+-dependent system(s). Glutamine uptake is not inhibited by N-methyl-D-L-alanine or 2-(methylamino)-isobutyric acid which are inhibitors of the A system of transport. Calvaria, when incubated in vitro degrade significant amounts of glutamine to ammonia, glutamate, other amino acids (alanine, aspartate, proline, ornithine) and CO2. The purpose of this report is to further delineate several of these processes with a view to their possible physiological significances.
KeywordsAmmonia Production Glutamine Concentration Isobutyric Acid Amino Acid Transport System Glutamine Uptake
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