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

The morphological maturation and the distribution of brush border hydrolase activities were studied in the small intestine and the colon in newborn babies of 28-38 weeks gestational age. Lactase and sucrase activities were higher at term with maximal activity in the proximal intestine. In contrast, aminopeptidase and glucoamylase exhibited maximum activity in the distal part of the small bowel. Glucoamylase activity was already significant in the small intestine and in the colon of the preterm newborn. Sucrase activity present in the proximal colon of the preterm dropped to a negligible amount at term, whereas aminopeptidase activity increased, reaching values found in the small intestine. The enzymic changes occurring in the intestinal tract were related to the morphological maturation of the mucosa from fetal to adult type during late gestation. Accelerated morphological and functional maturation was observed in one preterm infant nourished intravenously for 12 days, these processes being independent of the presence of nutrients in the intestine. At term, the distal part of the intestine seems to have increased digestive capacities for peptides and polysaccharides. We present evidence that full-term, and to a lesser extent preterm infants are able to hydrolyse glucose polymers.
 ...
PMID:Longitudinal distribution of brush border hydrolases and morphological maturation in the intestine of the preterm infant. 308 71

Intralipid was given to adult rats for 4 days either by intragastric or intravenous infusion. The villus height, protein content and the levels of sucrase, lactase and aminopeptidase activities were determined in the jejunum. The results were compared to values found in control rats fed orally with an equilibrated isocaloric diet. Intragastric or intravenous infusion of Intralipid caused a 50% reduction in the protein content of the brush border membrane, a significant drop of the specific (expressed per milligram protein) and segmental (expressed per centimeter intestinal length) activities of the disaccharidases, the maintenance of aminopeptidase activity and the lengthening of the villi in the jejunum. The major loss in disaccharidase activities was obtained when fat was given intravenously. Arguments favoring a hormone-mediated effect of the infused lipids on the intestinal function are presented and discussed.
 ...
PMID:Effect of intravenous and intragastric fat infusion on intestinal brush border enzyme activities in rats. 308 1

Morphologic and functional adaptations of the functioning intestine were evaluated in 41 patients before and after biliopancreatic bypass for morbid obesity. This surgical procedure diverts pancreatobiliary secretions via the duodenum and the jejunum into the colon, the remaining small intestine being anastomosed to the stomach after antrectomy. In the proximal ileum there was an 80% increase of the height of villi; the specific activities of maltase, sucrase, and aminopeptidase in brush border membranes remained unaffected, and that of lactase tended to decrease. In the distal ileum villi heights increased only by 58%, and disaccharidase activities (except for maltase) were slightly enhanced. In the colon the mucosa displayed, in some patients, focal appearance of true villi, and brush border enzyme activities increased concomitantly. We conclude that biliopancreatic bypass induces an adaptation of all intestinal segments of the functioning intestine; this adaptation tends to compensate for the shortening of the gut continuity.
 ...
PMID:Small-intestinal and colonic changes after biliopancreatic bypass for morbid obesity. 310 Nov 67

To investigate the adaptation of functions expressed by the villous and crypt cell of the intestinal mucosa after intestinal resection, a 50% proximal enterectomy or a single transection was performed in 16 growing rats weighing 175-200 g. Ten days following the enterectomy, we determined the mucosal mass parameters (weight, protein, and DNA content), the activity of microvillous enzymes (lactase, sucrase, and aminopeptidase) in villus cells, and the concentration of the secretory component of immunoglobulins in crypt cells isolated from the proximal intestinal remnant. Mucosal hyperplasia was attested by the finding that mucosal weight, protein, and DNA content per cm of intestinal length were significantly (p less than 0.01) higher (+29 to +48%) in the resected group than in transected controls. The specific activity of lactase, sucrase, and aminopeptidase were significantly (p less than 0.05) lower (-23 to -56%) in villous cells isolated from the intestinal remnant of resected rats compared to controls. Sucrase activity was depressed in each cell fraction of the entire villous-crypt unit resulting in a lower villous to crypt gradient of enzyme activity. Km for the enzyme determined in villous cells was similar in both groups but the Vmax was reduced proportionally to the enzyme activity in the resected group indicating less enzyme per cell. By contrast, the concentration of secretory component measured by an immunoradiometric assay in both villous and crypt cells was significantly (p less than 0.05) increased (+37 to 45%) following proximal enterectomy. Our data indicate that the response of the epithelial cell to intestinal resection varies according to the metabolic function and that the mechanism of adaptation at the cellular level is complex.
 ...
PMID:Cellular adaptation of the rat small intestine after proximal enterectomy: changes in microvillous enzymes and in the secretory component of immunoglobulins. 311 6

Intestinal hydrolase activities were studied during postnatal development in the offspring of rats exposed to 20% ethanol during gestation; alcohol was withdrawn at birth. Controls received water during gestation. Sucrase, lactase, glucoamylase and aminopeptidase activities were determined 2 and 4 weeks after birth in the proximal jejunum. Offspring prenatally exposed to ethanol showed a deficit in body weight and lower aminopeptidase activity during the suckling period (2 weeks). These effects were reversible by 4 weeks when alcohol was withdrawn at birth. The prenatal exposure to ethanol did not change the pattern of sucrase maturation in the intestine of offsprings. The activities of lactase and glucoamylase were not modified following prenatal exposure to ethanol. In conclusion, exposure to ethanol during gestation caused decreased abilities for the intestine of the offspring to digest protein.
 ...
PMID:Prenatal exposure to alcohol in rat: effect on intestinal enzymes in offspring. 311 99

The influence of insulin on the postnatal development of intestinal functions linked to villus cells (sucrase, lactase, maltase and aminopeptidase) and crypt cells (secretory component of immunoglobulins, SC) has been studied in suckling and weanling rats. At 9 days of age, the animals received a daily injection of insulin 12.5 mU g-1 body weight day-1 for 4 days. Compared with saline-treated controls, insulin had no effect on the development of the intestinal mucosal mass parameters determined in the jejunum, ileum and colon. A premature appearance of sucrase was noted in isolated jejunal villus and crypt cells, the level of activity reached by the enzyme being dependent of the amount of insulin injected. By 6 and 12 h after a single injection of the hormone (12.5 mU g-1 body weight), sucrase activity was detected in all the cell fractions along the villus-crypt axis. In villus cells of insulin-treated rats, maltase, lactase and aminopeptidase activities were significantly (P less than 0.001) increased (+201%, +50%, +207%, respectively, vs. controls), whereas the concentration of SC measured by a sensitive immunoradiometric assay was enhanced over the controls by 75% in villus cells, 83% in crypt cells and 172% in the liver. Weanling rats treated from day 10 to day 20 postpartum with 12.5 mU insulin also exhibited a higher intestinal production of SC (+93%, P less than 0.01) than did saline controls.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Intestinal development in the suckling rat: effect of insulin on the maturation of villus and crypt cell functions. 313 25

Intestinal morphology and brush border hydrolase activities were determined along the small intestine of young adult (three months, n = 10), mature (12 months, n = 10), and senescent (29 months, n = 15) rats. The intestinal segments of the senescent rats contained higher mucosal mass and protein content (p less than 0.05) compared with the young and mature animals. A significant reduction of villus height and crypt depth (p less than 0.05) was found in the proximal intestine during aging. A 35% increase in villus height (p less than 0.05) without changes in crypt depth, was observed in the distal ileum in senescent rats. The activities of sucrase and isomaltase were significantly increased during aging in the duodenum and jejunum (p less than 0.05). Lactase and aminopeptidase activities which showed only minor changes between young and mature animals were significantly enhanced in senescent animals (p less than 0.05) with aminopeptidase exhibiting a three-fold increase in activity in the proximal ileum. The results when combined with those of previous studies suggest that in the aged animal, the increased level of intestinal hydrolase activities may be the consequence of prolonged cellular maturation along the villi in the proximal intestine, and of adaptation to increased concentrations of intraluminal substrates in the distal intestine.
 ...
PMID:Age related increase of brush border enzyme activities along the small intestine. 320 13

We studied 24 patients with end-stage chronic renal failure not treated with hemodialysis (CRF1) and 16 patients on regular hemodialysis (CRF2), to investigate the digestive, absorptive and morphological aspects of the small intestinal mucosa. Serum d-xylose test and biochemical parameters of absorption (serum calcium and proteins) were determined. Jejunal mucosal biopsies were obtained and tissue homogenates assayed for disaccharidases (sucrase, maltase and lactase) and dipeptidases (glycyl-glycinase, leucyl-glycinase and leucyl-aminopeptidase). Histological changes were classified according to the severity of abnormality and compared with biopsies obtained from control subjects. Serum d-xylose test, calcium and proteins were normal in patients with CRF. Maltase specific activity was higher in CRF1 than in controls (p less than 0.05). Lactase and leucyl-aminopeptidase showed a tendency to decrease in CRF, but this difference did not reach statistical significance. Sucrase, glycyl-glycinase and leucyl-glycinase specific activity in CRF was similar to the control group. Histological changes of the small intestinal mucosa of mild to moderate degree were noted in 68% of patients with CRF vs 36% in control subjects (p less than 0.01). No significant difference was noted in the incidence of absorptive, enzymatic (with the exception of maltase) and histological changes between the two groups of patients with CRF. These changes are not influenced by hemodialysis, a long-term treatment averaging 6 months, they appear to represent primary manifestations of CRF and may be related to the nutritional status of patients with CRF.
 ...
PMID:Small intestinal function and structure in patients with chronic renal failure. 339 24

We studied the activity and kinetic parameters of microvillous enzymes in intestinal villous cells and the concentration of the secretory component (SC) of p-immunoglobulin A in subcellular fractions of crypt cells in 35-day-old rats made iron deficient from birth and in controls. The aim of the study is to investigate the biochemical basis for the decreased activity of brush-border disaccharidases observed in growing animals with chronic iron deficiency. In rats made iron deficient, the specific (per unit protein) and the total (per total intestinal length) activities of sucrase, lactase, maltase, aminopeptidase, and diamine oxidase were decreased from -17 to -66% compared with the activities measured in the controls. The lower activity of sucrase in the brush-border membrane of the iron-deficient rats was associated with much slower enzyme synthesis rate than in control animals. Km of sucrase was identical in both iron-deficient rats and controls, but the maximum velocity of enzyme reaction was reduced proportionally to the enzymatic activity, indicating a lesser amount of enzyme rather than an inactivation. Electron microscopy of epithelial villous cells from iron-deficient rats revealed a marked rarefaction of secretory granules (transport vesicles) without apparent change in the morphology of the brush-border membrane or of cellular organelles. In villus and crypt cells isolated from the jejunum of iron-deficient rats, SC concentration was reduced to a level about half that of the controls. When SC concentration was measured in subcellular fractions of crypt cells, SC content in each fraction was two to three times lower in iron-deprived rats than in controls without evidence of accumulation of the protein at a given subcellular level.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Alteration of intracellular synthesis of surface membrane glycoproteins in small intestine of iron-deficient rats. 378 40

Highly purified microvillus membrane vesicles isolated from rat small intestine were enriched in sucrase, maltase, and aminopeptidase activities. Approximately 90-95% of each enzyme was released from the membrane fraction by treatment with detergent (Triton X-100) and sonication. Using untreated and solubilized preparations, the effect of lectin binding on the activity of each of the three enzymes was measured. It was observed that wheat germ agglutinin (WGA) and phytohemagglutinin (PHA) dramatically enhanced the activity of membrane-bound maltase but had much less effect on the detergent solubilized enzyme. Under the same conditions aminopeptidase activity was inhibited by WGA and PHA while sucrase activity was not affected. These alterations in enzyme activity occurred at lectin concentrations that also precipitated each solubilized enzyme from solution. Inhibitory sugars prevented the alterations in enzyme activity suggesting that the effect is due to the binding of lectin to specific carbohydrate structures. Enhancement of membrane-bound maltase activity by WGA and PHA was shown to be temperature dependent indicating that the lipid environment of the microvillus membrane may play a role in mediating the lectin effect. A kinetic analysis of the changes in maltase activity induced by these two lectins was due solely to an increase in Vmax. Two other lectins used in this study (concanavalin A and Ricinus communis agglutinin) did not readily precipitate the enzymes in question or alter their activity. These results show that binding of lectins to brush border membranes can induce variable changes in the activity of several membrane associated hydrolases, and suggest that similar changes may occur in vivo in the presence of dietary lectin.
 ...
PMID:Effect of lectins on the activity of brush border membrane-bound enzymes of rat small intestine. 390 78


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>