caa a22 4500 388062223 CHVBK 20180307125124.0 cr unu---uuuuu 161130e199804 xx s 000 0 eng 10.1079/BJN19980061 doi S0007114598000622 pii (NATIONALLICENCE)cambridge-10.1079/BJN19980061 Glutamine metabolism in the gastrointestinal tract of the rat assessed by the relative activities of glutaminase (EC 3.5.1.2) and glutamine synthetase (EC 6.3.1.2) [Elektronische Daten] The activities of the two key enzymes involved in glutamine metabolism, glutaminase (EC 3.5.1.2) and glutamine synthetase (EC 6.3.1.2), have been measured in the various tissues of the gastrointestinal (GI) tract of the rat, from the mouth to the rectum. Glutaminase activity was particularly high in the mucosa of the small intestine, where its activity accounted for more than 80% of the total activity of the GI tract. In contrast, the mouth and oesophagus had very low activities, accounting for less than 2% of the total. Glutamine synthetase was mainly confined to the lower part of the stomach, which accounted for almost 90% of the total activity of the GI tract. Activity in the small intestine was very low, accounting for less than 2% of the total, and similarly low levels were found in the mouth and oesophagus. The data provide the most complete information on the distribution of these enzymes in the GI tract of the rat and suggest: (a) that the mucosa of the small intestine has the highest capacity for glutamine breakdown but the lowest capacity for its synthesis, and so requires an external source of this amino acid; (b) that there is little potential for glutamine synthesis or breakdown in the mouth and oesophagus; and (c) that the lower stomach has a substantial capacity to synthesize glutamine, in contrast to the rest of the GI tract. The results of the investigation are relevant to sites of glutamine metabolism in therapeutic studies involving glutamine administration discussed with reference to reports of the effects of glutamine administration on GI tract injury. Copyright © The Nutrition Society 1998 Gastrointestinal tract nationallicence Glutaminase nationallicence Glutamine synthetase nationallicence Rat nationallicence James L. A. MRC Dunn Nutrition Centre, Downham's Lane, Milton Road, Cambridge CB4 1XJ, UK Lunn P. G. MRC Dunn Nutrition Centre, Downham's Lane, Milton Road, Cambridge CB4 1XJ, UK Elia M. MRC Dunn Nutrition Centre, Downham's Lane, Milton Road, Cambridge CB4 1XJ, UK British Journal of Nutrition Cambridge University Press 79/4(1998-04), 365-372 0007-1145 79:4<365 1998 79 BJN https://doi.org/10.1079/BJN19980061 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1079/BJN19980061 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- James L. A. MRC Dunn Nutrition Centre, Downham's Lane, Milton Road, Cambridge CB4 1XJ, UK NATIONALLICENCE 700 1- Lunn P. G. MRC Dunn Nutrition Centre, Downham's Lane, Milton Road, Cambridge CB4 1XJ, UK NATIONALLICENCE 700 1- Elia M. MRC Dunn Nutrition Centre, Downham's Lane, Milton Road, Cambridge CB4 1XJ, UK NATIONALLICENCE 773 0- British Journal of Nutrition Cambridge University Press 79/4(1998-04), 365-372 0007-1145 79:4<365 1998 79 BJN CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge