Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gut atrophy develops during prolonged total parenteral nutrition (TPN). TPN solutions do not contain glutamine, an energy substrate of the intestinal tract. This study evaluated the effect of addition of L-glutamine to TPN on gut nitrogen content, histology, and disaccharidase enzyme activity. Five groups of six Fisher 344 rats received rat chow, D5W, TPN (23% calories as lipid), or TPN with 1 or 2% L-glutamine. Animals given TPN received 30 kcal and 0.22 g nitrogen/100 g/day. Metabolic cages allowed nitrogen balance for each group. After 6 days infusion, stomach, small bowel, and colon were assayed for total nitrogen and sucrase, lactase, and maltase activity. Mucosal height and fatty infiltration of the liver were determined from histologic sections. Adding either 1 or 2% L-glutamine resulted in no toxic clinical effects. Glutamine preserved intestinal nitrogen content of the stomach and colon compared to standard TPN and increased nitrogen content of small bowel to greater than that in chow-fed animals. Glutamine maintained mucosal height of the stomach and colon, but was no better than TPN alone in maintenance of small bowel mucosal height. One percent glutamine increased and standard TPN depressed maltase activity compared to chow. Standard TPN and 1% glutamine both stimulated sucrase and lactase activity compared to chow. Addition of 1 or 2% glutamine protected the liver from fatty infiltration seen with standard TPN. These studies would suggest the addition of glutamine might be beneficial during provision of standard total parenteral nutrition.
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PMID:Use of L-glutamine in total parenteral nutrition. 313 88

Glutamine (GLN) is an important fuel and epidermal growth factor (EGF) is a potent mitogen for intestinal mucosa cells. GLN-enriched parenteral nutrition was administered to male Wistar rats, and subcutaneous injections of EGF were given for 3, 6, and 7 days. Control animals were fed a non-GLN-containing solution. Other groups of animals received GLN or EGF alone. Mucosal samples were obtained from the jejunum, ileum, and colon for measurement of weight, DNA, protein, and mucosal thickness. Disaccharidase activity was measured in the jejunum. After 3 days, only animals that received both GLN and EGF had a significant increase in small-bowel mucosal protein and thickness relative to controls. A similar pattern was observed in the colon, where animals that received both agents had a greater mucosal thickness, DNA, and protein content than controls. At 7 days, animals that received EGF or GLN had greater nitrogen retention. In addition, animals that were treated with EGF had elevated sucrase and maltase activity compared with GLN-fed animals at this time. Animals treated with GLN and EGF tended to have increased sucrase activity relative to controls. GLN feeding was associated with increased mucosal DNA and protein contents throughout the intestine for the combined series. EGF increased mucosal DNA and protein in the small intestine but not in the colon. The effect of EGF on the protein content of the small-bowel mucosa was dose dependent. The effects of GLN and EGF on the small bowel and colonic mucosa were additive. These studies suggest that specific nutrients and hormones may be used in combination to decrease the mucosal atrophy that commonly occurs after gut disuse or disease.
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PMID:Combined effects of glutamine and epidermal growth factor on the rat intestine. 313 28

Glutamine is the major fuel for enterocytes and prevents mucosal atrophy in certain animal models. Previous studies in our laboratory have failed to show a trophic effect of glutamine on the small-bowel mucosa following massive resection when added to a chow diet. However, the complexity of the chow diet might potentially interfere with the adequate evaluation of the trophic effect of a single agent such as glutamine. This study was therefore designed to determine whether the addition of glutamine to an elemental diet would augment mucosal adaptation following massive small intestinal resection in a rat model. Male Sprague-Dawley rats were divided into two dietary groups, one receiving an amino acid-based pediatric elemental diet supplemented with 2% glutamine, and the other receiving the diet supplemented with 2% glucose. One half of the animals in each dietary group received 80% jejunoileal resection, and the remainder were sham operated. Fifteen days postsurgery, mucosal weight, DNA, protein, and sucrase activities were determined in both the proximal and the distal small intestine. While both groups of resected animals developed marked increases in all parameters of adaptation, the glutamine-supplemented group did not differ from the control diet group in any parameter. The addition of glutamine to an elemental diet had no enhancing effect on intestinal adaptation after bowel resection. These results are similar to those previously observed in our laboratory when glutamine was added to chow diet. The addition of glutamine to an elemental diet cannot be justified on the basis of its trophic effect in animals.
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PMID:Effect of glutamine-supplemented elemental diet on mucosal adaptation following bowel resection in rats. 858 90

Callus cultures derived from pith tissue of Nicotiana tabacum were grown on two media either under continuous illumination or in complete darkness. The first medium limited greening ability of callus grown in the light (3 milligrams per liter naphthalene acetic acid, 0.3 milligram per liter 2-isopentenylaminopurine, Murashige and Skoog salts, and 2% sucrose). The second medium encouraged chlorophyll synthesis (greening) though not shoot formation (0.3 milligram per liter naphthalene acetic acid; 0.3 milligrans per liter 2-isopentylaminopurine). To measure intracellular concentrations, calli were grown for 15 days on these standard media containing [U-(14)C]sucrose. The dry weight proportions of the calli (as a fraction of fresh weight) and many metabolite concentrations nearly doubled in light-grown cells compared to dark-grown cells and increased 30 to 40% on low-auxin media relative to high-auxin media. Glutamine concentrations (from 4 to 26 millimolar) were very high, probably due to the NH(3) content of the media. Proline concentrations were 20-fold higher in calli grown on low-auxin media in the light (green cells), possibly a stress response to high osmotic potentials in these cells. To analyze sucrose metabolism, callus cells were allowed to take up 0.2% (weight per volume) [U-(14)C]sucrose for up to 90 minutes. In callus tissues and in pith sections from stems of tobacco plants, sucrose was primarily metabolized through invertase activity, producing equal amounts of labeled glucose and fructose. Respiration of (14)CO(2) followed the labeling patterns of tricarboxylic acid cycle intermediates. Photorespiration activity was low.
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PMID:Intracellular concentrations and metabolism of carbon compounds in tobacco callus cultures: effects of light and auxin. 1666 13

The rate of carbon and nitrogen assimilation is highly sensitive to stress factors, such as low temperature and drought. Little is known about the role of light in the simultaneous effect of cold and drought. The present study thus focused on the combined effect of mild water deficiency and different light intensities during the early cold hardening in durum wheat (Triticum turgidum ssp. durum L.) cultivars with different levels of cold sensitivity. The results showed that reduced illumination decreased the undesirable effects of photoinhibition in the case of net photosynthesis and nitrate reduction, which may help to sustain these processes at low temperature. Mild water deficiency also had a slight positive effect on the effective quantum efficiency of PSII and the nitrate reductase activity in the cold. Glutamine synthesis was affected by light rather than by water deprivation during cold stress. The invertase activity increased to a greater extent by water deprivation, but an increase in illumination also had a facilitating effect on this enzyme. This suggests that both moderate water deficiency and light have an influence on nitrogen metabolism and sucrose degradation during cold hardening. A possible rise in the soluble sugar content caused by the invertase may compensate for the decline in photosynthetic carbon assimilation indicated by the decrease in net photosynthesis. The changes in the osmotic potential can be also correlated to the enhanced level of invertase activity. Both of them were regulated by light at normal water supply, but not at water deprivation in the cold. However, changes in the metabolic enzyme activities and osmotic adjustment could not be directly contributed to the different levels of cold tolerance of the cultivars in the early acclimation period.
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PMID:Reduced light and moderate water deficiency sustain nitrogen assimilation and sucrose degradation at low temperature in durum wheat. 2678 56