Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hydrocortisone administration to infant rats enhanced cellobiase and maltase activities and induced precocious expression of sucrase and trehalase activities along the length of the small intestine. These activity changes reflected proportional concentration increases in the enzymes lactase (EC 3.2.1.23), maltase/glucoamylase (EC 3.2.1.20) and sucrase-isomaltase (EC 3.2.1.48/10). Administration of an equivalent tracer dose of [3H]leucine (by body weight) to control and hydrocortisone-treated infant rats resulted in greater accumulation of label in the carbohydrase pools of the treated rats, suggesting their increased de novo synthesis. The increased concentrations of lactase and maltase/glucoamylase induced by exogenous hydrocortisone were matched by the presence of corresponding greater amounts of label in their brush border pools. Accumulation of label in each of the lactase, maltase/glucoamylase and sucrase-isomaltase pools was generally similar in the hydrocortisone-treated rats, suggesting equivalent stimulation of their synthesis as a group by the humoral agent. The turnover rates of the carbohydrases as a group were found to be similar and did not appear to differ in control and hydrocortisone-treated rats. Total protein synthesis rates were slightly greater in the intestine of the hydrocortisone-treated group of rats.
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PMID:Effects of hydrocortisone on carbohydrase concentrations, de novo synthesis and turnover patterns in immature rat intestine. 308 73

Graft-versus-host reaction (GvHR) was induced in neonatal mice to produce crypt hyperplasia with and without stunted villi. Lactase activity was measured along individual villi of control and GvHR mice using quantitative cytochemistry. Lactase activity increased in control mice as enterocytes migrated over the lower part of the villus. This increase was followed by a period when lactase activity remained approximately constant. Effects produced by GvHR on this normal profile of development included an extension of the distance on the villus over which enterocytes could continue to increase lactase activity, a reduction in the time needed for an enterocyte to express lactase activity at maximal rate, and an overall decrease in the maximal lactase activity expressed by mature enterocytes. These effects have been quantified by fitting logistic curves to the experimental data. Parallel biochemical analyses of intestinal homogenates showed sucrase, isomaltase, trehalase and maltase activities to increase markedly 7-8 days after the injection of parental spleen cells. Attention is drawn to similarities between these results and steroid induced precocious development of intestinal function in neonatal mice.
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PMID:Selective effects of graft-versus-host reaction on disaccharidase expression by mouse jejunal enterocytes. 308 82

The development of the human fetal gastrointestinal tract takes place early during gestation. The pancreas although developed by morphological means at the 16th week of gestation excretes its exocrine enzymes later at the 24th week of gestation except for amylase which reaches its full activity 6 months after birth. Trypsinogen secreted at the 24th week is activated into trypsin by enterokinase at the 26th week of gestation whereas lipase and colipase are secreted from the 24th week. The small intestine starts developing at the 10th week morphologically and functionally. At the same time when villi and crypts start to develop at the 11th to 12th week the first enzyme activities can be detected, i.e. sucrase-isomaltase, maltase-glucoamylase and lactase. Also peptidases and lysosomal hydrolases are measured at this age. With the exception of lactase, intestinal enzymes reach sufficient activities at the 25th week of gestation. Lactase activity remains low until the 32nd-34th week. For the digestion and absorption of lipids, protein and carbohydrates the gastrointestinal tract of premature infants under 1500 g in rather well equipped. Lipids are hydrolysed by the mutual action of breast milk lipase, lingual lipase, gastric lipase and pancreatic lipase. The carbohydrates lactose and oligosaccharides as supplements to breast milk are hydrolysed by lactase, sucrase-isomaltase and maltase-glucoamylase. Breast milk proteins and cows milk hydrolysates are digested by pancreatic proteases into oligopeptides which can be hydrolysed within the lumen by brush border peptidases and be absorbed. Peptides also can actively be transported through the microvillus membrane and be hydrolyzed by intracellular peptidases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Nutrition of premature infants below 1,500 g: enteral prerequisites]. 309 34

The influence of pancreatic secretions on growth and brush-border enzyme activity, throughout the entire small intestine, was examined in the rat. Pancreatic secretions were excluded from the gut lumen by stapling the pancreatic ducts, without interruption of bile flow. The entire small intestine was studied as four segments; the duodenum and three distal segments of equal length. Weight of intestine and mucosa, and mucosal sucrase, isomaltase, lactase, and alkaline phosphatase activity were measured 10-15 days following pancreatic duct occlusion, or sham-operation. The duodenum of pancreatic duct-occluded animals exhibited significant hypertrophy. In general, specific and total disaccharidase activities were greater in duct-occluded animals than in controls throughout the intestine. The increase was more pronounced in distal than in proximal segments. The sucrase/isomaltase ratio was significantly greater in pancreatic duct-occluded animals than in controls in the two distal segments. Alkaline phosphatase activity was not affected by pancreatic duct occlusion. The greater relative increase of disaccharidase activities and sucrase/isomaltase activity ratios in the distal segments of duct-occluded animals, indicates a more important regulatory role of pancreatic enzymes in the distal small intestine. It is concluded that regulation of intestinal brush-border enzyme activity by pancreatic secretion is selective for enzyme and site as follows: disaccharidases, but not alkaline phosphatase, are regulated; the sucrase subunit of the sucrase/isomaltase complex is most sensitive to regulation, while lactase is least sensitive; and the regulatory effect on disaccharidases is greater in distal than in proximal intestine.
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PMID:Intestinal disaccharidase activity following pancreatic duct occlusion in the rat. 311 40

The results of studies on disaccharidase activities and on intestinal absorption in cases of complete and incomplete congenital small bowel obstruction are presented. Assays of the activities of maltase, isomaltase, sucrase, trehalase, and lactase have been performed on biopsy specimens taken at the time of surgery. In specimens taken from above the site of obstruction, the activities are reduced for all disaccharidases, and are particularly low for trehalase and lactase. There was no difference between the cases with complete and incomplete obstruction. Distal to a complete obstruction, trehalase and lactase were reduced, whereas in cases of incomplete obstruction, the activities of all disaccharidases were within what is considered normal in the reference material. Two months after surgery, the disaccharidase activities were found to be normal. One month after surgery, the absorption of glucose and vitamin A was markedly impaired in cases with complete obstruction, whereas that of D-xylose was not significantly reduced from normal. In cases with incomplete obstruction, the results did not differ from those found in normal infants. The fact that failure to thrive is common during the first months after birth in patients with congenital intestinal atresia, even when surgery is successful, may be explained by deficient intestinal absorption, particularly in patients with complete obstruction.
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PMID:Disaccharidase activities and intestinal absorption in infants with congenital intestinal obstruction. 312 31

Results of disaccharidase assays in small bowel biopsies from 887 children over a 3 year period were analysed to establish normal values. Abnormal histology, the presence of giardia trophozoites or total absence of sucrase and isomaltase were found in 307 cases and these were excluded from further consideration. The results for maltase, sucrase and lactase from the remaining 580 children have been graphed as percentiles at various ages. They represent results which are as close to normal as it is possible ethically to obtain.
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PMID:'Normal' disaccharidase levels in children. 312 60

1. The intestinal disaccharidase activities of a suckling crabeater seal were investigated. 2. Lactase, maltase, isomaltase and cellobiase activities were readily detected but trehalase and sucrase activities were absent. 3. The intestinal homogenates were separated into a soluble (S2) fraction and a particulate brush border (P2) fraction. The lactase activities of the two fractions had different properties corresponding to those of an acid and a neutral beta-galactosidase respectively. Approximately two-thirds of the total lactase activity measured at pH 6.0 was due to the acid beta-galactosidase. 4. The isomaltase and cellobiase activities were found almost exclusively in the particulate fractions but about one third of the maltase activity was in the S2 fraction. This soluble maltase activity appeared to be due to an acid maltase.
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PMID:Intestinal lactase and other disaccharidase activities of a suckling crabeater seal (Lobodon carcinophagus). 313 70

To assess the course of recovery of gluten sensitive enteropathy in adults, histological and functional recovery was studied in 22 patients, aged 20-79 years. Biopsy specimens taken at the time of diagnosis were studied in 20; after adhering to a gluten free diet for nine to 19 (mean 14) months in 14; and after adhering to the same diet for 24-48 (mean 34) months in 10 patients. Histological recovery was assessed morphometrically in the proximal jejunum. Mucosal linings significantly improved over time, but did not completely return to normal with a gluten free diet: at diagnosis the surface: volume ratio was 22% of normal, increasing to 48% and 66% after nine to 19 and 24-48 months, respectively, of a gluten free diet. Disaccharidase activities progressively increased. After 24-48 months maltase, sucrase, and isomaltase had returned to normal in the proximal jejunum; they were still significantly decreased in the distal duodenum. Duodenal and jejunal lactase activities were both below normal after 24 to 48 months. It is concluded that recovery of the intestinal mucosa of adults with gluten sensitive enteropathy during a gluten free diet continues beyond nine to 19 months and is still incomplete after two to four years. The recovery of disaccharidase activities extends from the distal to the proximal part of the small intestine, and is aligned to histological recovery.
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PMID:Slow and incomplete histological and functional recovery in adult gluten sensitive enteropathy. 317 Jul 77

Effects of diet, hibernation and seasonal variations on hydrolase activities were determined in mucosa and purified brush border membranes of the small intestine of European hamsters. Wild hamsters captured in April and fed for several weeks with an equilibrated laboratory chow (20% protein, 50% carbohydrates) exhibited a rise in disaccharidase activities (sucrase, isomaltase, lactase) but no changes in aminopeptidase N activity. During deep hibernation, in contrast to sucrase and isomaltase activities which showed only minor changes, lactase activity was significantly enhanced along the jejunoileum, and aminopeptidase N activity was maximum in the ileum. After a short period (48 h) of wakefulness and feeding following 10 days of starvation during the hibernation period, the activities of the disaccharidases and of aminopeptidase N returned to values measured in active animals. In contrast to the nutritional state, which has an important impact on the activities of intestinal enzymes, season has little effect on the intestine of the active animal under a controlled environment. The pattern of enzyme activities which occurs along the small intestine in the hibernating animal may be a prerequisite for optimum digestion during the short phases of waking during the hibernation period of the European hamster.
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PMID:Adaptation of intestinal enzymes to seasonal and dietary changes in a hibernator: the European hamster (Cricetus cricetus). 317 Aug 22

MDL 25,637 is a novel compound designed as a transition-state inhibitor of alpha-glucohydrolases. This compound inhibits rat intestinal sucrase, maltase, isomaltase, glucoamylase and trehalase activities at micromolar concentrations. It is a much weaker inhibitor of alpha-amylase and lactase. Inhibition of sucrase was competitive with sucrose. In mice, MDL 25,637 inhibited the rise in serum glucose after a sucrose or starch load but not after a glucose load. MDL 25,637 also reduced the glycemic response to sucrose in rats. The drug was most effective when administered 0 to 30 min before the sucrose load and was as effective in streptozotocin-treated rats as in normals. The inhibition by MDL 25,637 of intestinal glucohydrolases is an effective means of reducing the hyperglycemic response to an oral sucrose or starch load and, as such, warrants further investigation as a potential drug for the treatment of diabetes mellitus.
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PMID:Inhibition of intestinal disaccharidases and suppression of blood glucose by a new alpha-glucohydrolase inhibitor--MDL 25,637. 329 22


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