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)

The influence of hydrocortisone (10(-8)--10(-5) M) and thyroxine (10 (-9)--10(-6) M) on intestinal epithelial cell differentiation and proliferation have been studied using explants of suckling mouse jejunum maintained in serum-free organ culture. Hydrocortisone induced the appearance of sucrase activity and increased trehalase, glucoamylase, lactase and alkaline phosphatase activities. Thyroxine was completely ineffective at all the concentrations used. None of these hormones affected the mitotic activity or the 3H-thymidine incorporation into DNA. These results demonstrate that hydrocortisone but not thyroxine acts directly on intestinal brush border membrane differentiation and that both hormones do not influence the proliferation of the epithelial cells during postnatal development.
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PMID:Comparative study of the effect of hydrocortisone and thyroxine on suckling mouse small intestine in organ culture. 614 44

Explants of suckling mouse jejunum have been maintained in serum-free organ culture with or without insulin added to the medium in order to determine the possible direct effect of this hormone on the hydrolytic functions of the brush border and on the proliferation of the crypt cells. The addition of insulin induced the precocious appearance of sucrase activity and increased trehalase, glucoamylase and lactase activities. Alkaline phosphatase activity remained unaffected in the tissue as well as in the medium. An increased DNA content and 3H-thymidine incorporation into DNA were already recorded after 24 h of culture. The mitotic index was significantly increased after 24 h and remained elevated when the culture was extended to 48 h. These results show that insulin directly influences the enzymatic maturation and the proliferation of intestinal epithelial cells of suckling mouse.
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PMID:Insulin influences the maturation and proliferation of suckling mouse intestinal mucosa in serum-free organ culture. 639 67

The development of small intestinal enzymes (lactase, acid- and hetero beta-galactosidases, cellobiase, maltase, trehalase, and sucrase) was studied from 18 days after conception until birth in 24 rabbit fetuses, and during the postnatal period in 15 newborn, juvenile, and adult rabbits. Lactase, acid- and hetero beta-galactosidases, cellobiase, and trehalase activities increased significantly during the fetal stage, while changes in sucrase and maltase activities were not substantial. In the postnatal period, lactase and cellobiase activities decreased significantly whereas maltase, sucrase, and trehalase activities increased significantly to reach adult values by 30 days of age. The acid- and hetero beta-galactosidases remained unchanged.
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PMID:The fetal and postnatal development of small intestinal disaccharidases in the rabbit. 643 Nov 90

Intestinal disaccharide uptake was studied with isolated brush-border membrane vesicles lacking the corresponding hydrolase. Either 15-day-old chick intestine, lacking both trehalase and lactase, or newborn pig intestine, lacking sucrase, was used. Both animal species yielded osmotically active vesicles capable of D-glucose/Na+ cotransport with a positive overshoot test. Vesicles from either origin gave quantitatively similar results in regard to both initial uptake rates and relative vesicle volumes. The nontransported analogs D-mannitol and L-glucose were used as diffusion markers. When tested with the appropriate disaccharidase-lacking vesicles, lactose, trehalose and sucrose exhibited uptake rates indistinguishable from those of D-mannitol and L-glucose. These uptakes were unaffected by the presence or absence of Na+, phlorizin and Tris. Chromatographic analysis confirmed the lack of hydrolysis of each disaccharide after prolonged incubation. The inescapable conclusion seems to be that intact disaccharides are not transported through the brush-border membrane, their uptake occurring through simple diffusion.
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PMID:Disaccharide uptake by brush-border membrane vesicles lacking the corresponding hydrolases. 643 45

Comparison of relative disaccharidase activities in jejunal mucosa, amniotic fluid, and meconium samples taken from the ileum, proximal and distal colon of 5 human fetuses, indicates that trehalase and lactase are more sensitive to the denaturation conditions existing in the fetal intestinal lumen than maltase, sucrase, palatinase and turanase . Relative activities of sensitive disaccharidases (trehalase and lactase) were also low in the amniotic fluid of these fetuses as compared to the jejunal mucosa. These results suggest that the in vivo stability of disaccharidases, exposed to proteolytic digestion and other denaturing conditions in the fetal intestinal lumen, governs the relative activities of these enzymes released into the amniotic fluid.
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PMID:Differential stabilities of fetal intestinal disaccharidases determine their relative amounts released into amniotic fluid. 672 23

Intestinal metaplasia is defined as the appearance of intestinal epithelium in the stomach. Intestinal metaplasia is frequently found in populations with a high incidence of gastric cancer. Macroscopic demonstration of sucrase and trehalase with Tes-tape in many resected stomachs yielded new information for understanding the nature of intestinal metaplasia. Intestinal metaplasia can be classified into two types, complete and incomplete. The former is associated with the presence of sucrase, trehalase, leucine aminopeptidase, alkaline phosphatase, goblet cells and Paneth cells, and the latter with that of sucrase, leucine aminopeptidase and goblet cells, but not trehalase or Paneth cells. Goblet cells in the complete type of intestinal metaplasia contain sialomucin, as does the small intestine, while those in the incomplete type contain sulphomucin and sialomucin, as does the large intestine. Well-differentiated adenocarcinoma is closely related to intestinal metaplasia, especially the incomplete type. Atypical epithelium of intestinal metaplasia has been proposed as a more proximate stage of gastric cancer. Intestinal metaplasia can be diagnosed by staining with dye under endoscopic observation. A reduced level of pepsinogen I in the blood reflects the presence of severe intestinal metaplasia, which is understood to be a sign of high risk of gastric cancer. Intestinal metaplasia is supposed to be produced by components of food. Mutagens/carcinogens such as N-methyl-N'-nitro-soguanidine and N-propyl-N'-nitro-N-nitrosoguanidine can produce intestinal metaplasia in the glandular stomach of rats and gastric cancers. The formation of intestinal metaplasia precedes the appearance of adenocarcinoma in the glandular stomach. Intestinal metaplasia, which is a kind of host reaction to environmental agents, may result either from genetic change - change in DNA structure - or from epigenetic change - change in the differentiation mechanism. Preventive measures could be developed to suppress the development of intestinal metaplasia and to suppress the process of conversion of metaplastic cells to cancer cells.
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PMID:Intestinal metaplasia of the stomach as a precancerous stage. 675 88

Rats were made severely uremic with partial nephrectomy (24-hour creatinine clearance 10% of normal). Jejunal dipeptidase activities (substrates: glycyl-L-leucine, L-alanyl-L-proline, and L-methionyl-L-methionine), disaccharidase activities (maltase, sucrase, trehalase, and lactase) and morphology were studied. A highly significant increase in glycyl-L-leucine and L-methionyl-L-methionine dipeptidases was found in uremic rats compared with controls. Proline dipeptidase activities were unaltered. Disaccharidase activities showed a slight increase in sucrase in uremic rats; otherwise no change was found.
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PMID:Small intestinal dipeptidases and disaccharidases in experimental uremia in rats. 677 73

The activities of various glycosidases in homogenates of the small intestinal mucosa of two adult and 18 suckling tammar wallabies (M. eugenii) aged from 6 to 50 weeks were investigated. Lactase (beta-D-galactosidase), beta-N-acetylglucosaminidase, alpha-L-fucosidase and neuraminidase activities were high during the first 34 weeks post partum and then declined to very low levels. Maltase, isomaltase, sucrase and trehalase activities were very low or absent during the first 34 weeks, and then increased. The lactase activity was unusual in being greater in the distal than the middle or proximal thirds of the intestine, and in its low pH optimum (pH 4.6), inhibition by p-chloromercuribenzene sulfonate but not by Tris, and lack of cellobiase activity. These properties are those of a lysosomal acid beta-galactosidase rather than of a brush border neutral lactase. The maltase activity had the characteristics of a lysosomal acid alpha-glucosidase early in lactation and of a brush border neutral maltase in adult animals. The significance of these findings is discussed in relation to changes in dietary carbohydrates during weaning and to the mode of digestion of milk carbohydrates by the pouch young.
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PMID:Intestinal lactase (beta-galactosidase) and other glycosidase activities in suckling and adult tammar wallabies (Macropus eugenii). 678 21

1. The levels of the brush-border enzymes sucrase (sucrose glucohydrolase, EC 3.2.1.48), isomaltase (oligo-1,6-glucosidase, EC 3.2.1.10), maltases 2 and 3 (glucoamylase, EC 3.2.1.3), lactase (beta-galactosidase, EC 3.2.1.23) and trehalase (EC 3.2.1.28) and adsorbed pancreatic alpha-amylase (EC 3.2.1.1) have been measured at twenty-one positions along the small intestines of eighty-four pigs of different ages ranging from 3 weeks to 4.5 years. The state of dilation of the intestine at the sampling points was noted. 2. The levels of sucrase and isomaltase increased with age throughout the age-range studied. Trehalase and the glucoamylases increased with age up to 200--300 d of age. Lactase decreased with age over the whole age range. 3. For the pigs above 10 weeks of age, the distribution pattern of the brush-border enzymes along the intestine did not change with age. Each enzyme had a characteristic distribution curve, with low values at the proximal and distal ends and a peak which was proximal in the instance of lactase and trehalase and approximately mid-way along the gut with sucrase, isomaltase and the glucoamylases. 4. The pattern of distribution of the brush-border enzymes altered with age in the piglets, but approached the adult pattern by 8 weeks. 5. Piglets weaned at 3 weeks had higher levels of sucrase, isomaltase and glucoamylases at 5 weeks than piglets left on the sow. At 8 weeks of age the piglets weaned at 3 weeks still had higher sucrase and isomaltase levels than those on the sow. 6. There was a very close correlation between the sucrase and isomaltase levels, and between the maltase 2 and maltase 3 levels in all the samples, and a fairly close correlation between all these four enzymes. 7. The level of alpha-amylase increased with age but showed no regular distribution pattern, its irregular fluctuations being related to the presence or absence of dilation of the intestine at the time of slaughter rather than to the position along the intestine.
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PMID:The level of distribution of carbohydrases in the small intestine mucosa of pigs from 3 weeks of age to maturity. 696 56

The intestinal brush-border disaccharidases most resistant to pancreatic protease digestion in vitro are lactase and trehalase. When compared to maltase and sucrase, they are also those which showed the largest increase during development of guinea pig fetuses. These results suggest that pancreatic proteases may play a role in the control of brush-border disaccharidase activities during fetal development.
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PMID:Control of disaccharidase activities in brush-border membranes of guinea pig fetuses: a role of pancreatic proteases? 702 47


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