Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of epidermal growth factor (EGF) on disaccharidase activity in intestinal epithelial cells were studied in mice. In salivectomised mice, the sucrase and maltase activities decreased significantly compared to the control group. When EGF was given to salivectomised mice, the sucrase and maltase activities rose, but still remained below the normal values. These results show that the submaxillary glands produced another factor, beside EGF, which induced glycoprotein enzyme formation in the Golgi complex.
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PMID:Effect of epidermal growth factor on disaccharidase activity in intestinal epithelial cells of mice. 191 36

Caco-2 cells, which express spontaneous enterocytic differentiation at confluency, is one of the most relevant in vitro models for the study of differentiation and regulation of intestinal functions. However, these cells are normally cultured in the presence of 15-20% serum which renders extremely complex the identification of the factors involved in the regulation of both proliferation and differentiation. This study has been devoted to the establishment of chemically defined culture conditions which can sustain growth and differentiation of Caco-2 cells. The replacement of serum by ITS (insulin, transferrin, and selenium) allowed for normal structural and functional differentiation of cells as revealed by the establishment of cell polarity and the expression of brush-border membrane enzyme markers (sucrase, maltase, lactase, alkaline phosphatase, gamma-glutamyltransferase, aminopeptidase N, and dipeptidyl-dipeptidase IV), although the levels of sucrase activity were lower in ITS-supplemented medium. Coating petridishes with either type IV collagen or basement membrane proteins (Matrigel) did not improve the differentiation of cells, brush-border membrane enzyme activities being, in fact, lower when the cells were grown on these substrata. When triiodothyronine (T3, 5 x 10(-8) M) was added to the ITS-supplemented medium, disaccharidase and alkaline phosphatase activities were significantly increased while gamma-glutamyltransferase activity was diminished by T3 and stimulated by epidermal growth factor (1.6 x 10(-6) M). On the other hand, hydrocortisone (HC, 10(-6) M) did not modify disaccharidase and peptidase activities. These data clearly show that Caco-2 cells can be maintained in serum-free medium and that this system allows the study of the factors involved in the regulation of the differentiation of enterocyte in vitro.
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PMID:Caco-2 cells cultured in serum-free medium as a model for the study of enterocytic differentiation in vitro. 193 45

The regulatory effect of epidermal growth factor (EGF) on the developmental pattern of brush border hydrolases was studied in the proximal jejunum and colon of the newborn rat. In the proximal colon, daily administration of EGF for 1, 3, or 5 days postpartum inhibited the postnatal increase in lactase, maltase, and aminopeptidase specific activities. In contrast, in the jejunum EGF did not influence lactase activity, inconsistently increased maltase activity, and partly prevented the early postnatal decrease in aminopeptidase activity. In the proximal colon, EGF showed additive effects with T4 and hydrocortisone on the inhibition of lactase activity. In the jejunum, EGF potentiated the effect of hydrocortisone and T4 on the expression of sucrase activity and had only a slight effect when injected alone. The incorporation rate of [3H]thymidine in the proximal colon and jejunum was not different in control and treated rats, indicating the absence of an effect of EGF on DNA synthesis. These results show that EGF may play an important physiological role in the enzymatic differentiation of the developing intestine during early postnatal development. Alone or acting with T4 or glucocorticoids, EGF may induce the decline of digestive hydrolases in the proximal colon. In the small intestine EGF may play a major role in the triggering of sucrase expression.
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PMID:Effect of epidermal growth factor on the expression of digestive hydrolases in the jejunum and colon of newborn rats. 211 92

The influence of epidermal growth factor (EGF) and hydrocortisone on the functional development of human fetal colon was studied in organ cultures. Fetal colon (14 to 17 weeks gestation) was cultured for 5 days at 37 degrees C in serum-free Leibovitz L-15 medium alone or supplemented with 1, 10, and 100 ng of EGF/ml or with 50 ng of hydrocortisone/ml of culture medium. The overall morphology of the colonic explants was not altered by the hormonal addition. In the continuous presence of EGF (1, 10, and 100 ng/ml) for 5 days, a significant decrease of [3H]thymidine incorporation into DNA was observed. At the brush border level, the addition of EGF induced a significant drop in sucrase, maltase, and alkaline phosphatase activities. These enzymic modifications occurred between the third and fifth day of culture, whereas variation in DNA synthesis was already evident within 24 h. The addition of hydrocortisone at a dose affecting the small intestine (50 ng/ml) did not significantly influence colonic DNA synthesis nor the digestive enzymic activities. These observations show for the first time that EGF, but not hydrocortisone, influences the proliferation and differentiation of human fetal colonic mucosa.
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PMID:Differential effects of epidermal growth factor and hydrocortisone in human fetal colon. 232 74

The postnatal development of brush border enzyme activities, namely maltase, trehalase, alkaline phosphatase, gamma-glutamyltranspeptidase, and leucylnaphthylamidase, as well as the ontogenic profile of DNA synthesis has been determined in the mouse kidney. In addition, these parameters were evaluated following daily administration of hormones during 3 days to 8-day-old mice. Insulin or epidermal growth factor induced a 34% increase of maltase activity over that of 11-day-old controls. Trehalase activity was precociously and significantly augmented by cortisone alone or combined with thyroxine (p less than 0.05), although thyroxine alone had no influence. Only epidermal growth factor had a significant effect on alkaline phosphatase activity. gamma-Glutamyltranspeptidase activity was significantly decreased when insulin and thyroxine were given simultaneously, but was not modified by any of the hormones injected separately. The level of leucylnaphthylamidase activity was enhanced by 70% after cortisone injection, but it was significantly reduced by thyroxine injected in combination with insulin or cortisone. The incorporation of [3H]thymidine into DNA was increased by 107% after epidermal growth factor administration, but it was decreased by 33% after the cortisone treatment. In spite of this precocious reduction, the level of incorporation was still 2 times higher than that in adult mice. These results show that hormones act separately or in cooperation to accelerate or retard the maturation of the suckling mouse kidney.
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PMID:Effect of hormones on hydrolase activities and DNA synthesis in kidney of the developing mouse. 290 Dec 85

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

1. Pig intestinal sucrase and maltase activities increase markedly, and lactase activity decreases, during the second week of post-natal life. Correlations noted between the time course describing these changes and that found previously to describe a decline in the ability of the pig intestine to take up macromolecules suggest that both events are subject to the same type of developmental control. 2. Injection of epidermal growth factor (EGF) into 3-day-old piglets increase sucrase and maltase activities measured 3 days later. These increases, which are not seen when measuring other hydrolase enzymes, are confined to the mid and distal regions of the small intestine. 3. Dexamethasone injected into 3-day-old piglets inhibits lactase and, on occasion, sucrase activities without affecting other intestinal hydrolases. Significant increases in sucrase and maltase activities also occur in distal intestine following injection of EGF plus dexamethasone into 3-day-old pigs. 4. Cytochemical analysis shows EGF effects on sucrase and maltase activities to be exerted in crypt and basal villus enterocytes produced post-natally. Dexamethasone inhibits lactase activity mainly by acting on mid and upper villus enterocytes produced before birth. 5. EGF appears to increase sucrase and maltase activities by extending the time during which young enterocytes continue to accumulate these enzymes in their brush-border membranes. Dexamethasone appears to cause a more fundamental change in the biochemistry of older enterocytes. accompanied by an increasing ability of these cells to transport neutral amino acids through a sodium-dependent mechanism (see James, Smith, Tivey & Wilson, 1987a).
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PMID:Epidermal growth factor selectively increases maltase and sucrase activities in neonatal piglet intestine. 332 84

The direct influence of epidermal growth factor (EGF) on the differentiation and proliferation of small intestine was studied in organ culture. Eight-day-old mouse small intestine was cultured during 2 days in serum-free Leibovitz L-15 medium alone or supplemented with EGF (50, 100, and 500 ng/ml) either at room temperature or at 37 degrees C. Brush border membrane hydrolytic activities, namely, sucrase, lactase, glucoamylase, trehalase, maltase, and alkaline phosphatase, were assayed in the intestinal tissue as well as in the culture medium. None of the brush border enzymic activities was affected by the addition of EGF to the culture medium. This lack of effect is not temperature dependent since it occurred both at room temperature and at 37 degrees C. The addition of hydrocortisone (10(-6) M) to the culture medium induced the appearance of sucrase activity and increased the activity of the other brush border enzymes. The simultaneous addition of EGF with hydrocortisone did not influence the response of the intestinal explants to hydrocortisone. The deoxyribonucleic acid (DNA) content was determined while DNA synthesis was evaluated by the incorporation of (3H)-thymidine. The addition of EGF did not affect DNA content or (3H)-thymidine incorporation into DNA either at room temperature or at 37 degrees C. The EGF binding to epithelial cells did not significantly vary throughout the culture period and a down-regulation process occurred in presence of EGF. These observations strongly suggest that EGF does not act as a primary cue for inducing developmental changes in suckling mouse small intestine. It is proposed that EGF induces a systemic reaction in vivo that then influences the neonatal small intestine.
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PMID:Epidermal growth factor does not act as a primary cue for inducing developmental changes in suckling mouse jejunum. 349 91

The purpose of this work was to study the direct influence of epidermal growth factor (EGF) on the maturation of the fetal mouse duodenum in organ culture. Duodenal explants, resected at 17 days of gestation, were cultured during 48 h at 37 degrees C in Leibovitz L-15 serum-free medium alone or supplemented with EGF (100 ng/ml). Differentiation of absorptive cells was evaluated by measuring brush border hydrolytic activities. After 48 h of culture with and without EGF, villous architecture and the fine structural characteristics of the tissues are preserved. In control explants, the level of alkaline phosphatase, maltase, trehalase, and sucrase activities as well as the protein and DNA contents remain comparable to the values measured in 17-day explants at the beginning of the culture period, while lactase activity falls drastically. In explants cultured with EGF, the level of alkaline phosphatase, maltase, and trehalase activities and the protein contents significantly increase while sucrase activity and DNA contents are unchanged, and lactase activity remains under the onset level. From these results, it was concluded that EGF influences directly the maturation of some brush border enzymes in the duodenum during the fetal period.
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PMID:Influence of epidermal growth factor on the maturation of the fetal mouse duodenum in organ culture. 387 51

The formation of intestinal villi (organogenesis phase) may be studied in organ culture with a completely synthetic medium in 15-day fetal mouse duodenal explants. However, in these explants absorptive cells remained poorly differentiated with all the hormones studied except with epidermal growth factor. In order to elucidate the role of hormones and other factors on the maturation of absorptive cells (maturation phase) in the fetal rodent in organ culture, we have taken the explants after the organogenesis phase. We have studied different culture conditions and have found that 17-day mouse duodenal explants can be cultured during 48 hours with Leibovitz L-15 medium in a 95% O2-5% CO2 atmosphere provided that the explants are relatively large (5 X 2 mm). With this method, dexamethasone (Dx) has been shown to have a direct effect on the maturation of the fetal duodenal mucosa. The addition of Dx (300 ng/ml) to the completely synthetic medium 1) improves the morphology of the explants, 2) induces a significant increase in maltase activity in the tissues, and 3) reduces significantly the labeling index of the duodenal explants after 48 hours of culture. Direct action of Dx on the duodenal mucosa is shown for the first time in organ culture using a completely synthetic medium. This method will permit us to study the effects of other intrinsic and extrinsic factors on the regulation of enzymatic maturation in fetal small intestine.
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PMID:Effect of dexamethasone on the fetal mouse small intestine in organ culture. 638 76


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