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)

To further document the effect of insulin on intestinal maturation, suckling rats were treated either with exogenous insulin (12.5 mU.g body wt, intraperitoneally, twice daily) or with saline from d 8 to 12 postpartum. Sucrase activity in brush border membrane extracts was precociously induced by insulin, whereas the activities of other brush border membrane enzymes (maltase, aminopeptidase, and neutral lactase) were enhanced (+ 30 to + 131%, p less than 0.01 versus controls). The lysosomal enzyme, N-acetyl-beta-glucosaminidase, which normally declines at weaning was significantly (p less than 0.025) decreased in both villus (-51%) and crypt cells (-57%) isolated from the jejunum of insulin-treated rats. The microsomal enzyme, sulfatase C, and the cytosolic enzyme, lactate dehydrogenase, were also sensitive to insulin with decreases in activity ranging from -37 to -63% (p less than 0.05) compared to saline-treated control rats. Insulin at doses of 0.5 or 12.5 mU did not influence plasma total corticosterone levels, which were about 9-fold lower in suckling than in 25-d-old weaned rats. In weaned rats (from d 25 to 32) insulin treatment (12.5 mU) failed to influence the activity of brush border membrane hydrolases or of lysosomal, microsomal, and cytosolic enzymes. The synthesis rate of mature sucrase-isomaltase, measured in weaned rats (32 d) by the incorporation of 14C-leucine into the enzyme precursor protein, was equivalent in both groups. These data demonstrate that the immature enterocyte of the suckling rat is responsive to insulin, whereas the mature enterocyte of the weaned rat is unresponsive.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hormonal regulation of the rat small intestine: responsiveness of villus and crypt cells to insulin during the suckling period and unresponsiveness after weaning. 217 34

The evolution pattern of brush-border digestive hydrolases and their hormonal regulation were studied in the proximal colon of newborn rats. The potentiality of the colon to express a small intestinal enzymatic pattern was also examined in associations made up of colonic endoderm and small intestinal mesenchyme, developed as either intracelomic grafts in 3-day-old chick embryos or as intrarenal grafts in adult rats. A transient increase of lactase- and aminopeptidase-specific activities occurred in the colon from the 19th day of gestation to 14 days after birth, but sucrase activity could never be detected. Immunocytochemical studies with antibodies specific for rat lactase, aminopeptidase, and sucrase confirmed these results. However, the levels of hydrolase activities were lower in the colon than in the jejunum at the same age. Thyroxine or hydrocortisone treatment during the first 4 days postpartum decreased lactase activity by 70 and 30%, respectively, but did not affect aminopeptidase activity. A slight but significant induction of sucrase activity was obtained with both hormones. In contrast, in the jejunum, only thyroxine decreased lactase activity with a lesser effect (30%), but both hormones increased aminopeptidase activity and induced the marked well-known appearance of sucrase activity. The fetal small intestinal mesenchyme was not able to induce the colonic endoderm to achieve a small intestinal-like differentiation. But the exposure of the developed hybrid intestines to glucocorticoids in organ culture allowed expression of sucrase in one-third of the cases. These results demonstrate the presence of brush-border hydrolases in the proximal colon of newborn rats, normally expressed in the small intestine, but never in the adult colon.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Perinatal expression of brush-border hydrolases in rat colon: hormonal and tissue regulations. 267 33

Juvenile white sturgeon were fed isonitrogenous diets containing 27.2% glucose, fructose, maltose, sucrose, lactose, dextrin, raw corn starch or cellulose for 8 wk. Growth, body composition, plasma chemistry (with the exception of glucose), and liver glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49), malic enzyme (EC 1.1.1.40) and isocitrate dehydrogenase (ICDH, 1.1.1.42) activities of sturgeon were significantly (P less than 0.05) affected by the different dietary carbohydrate sources. Sturgeon fed either the maltose or glucose diets had the highest percent energy retained, followed by those fed either the dextrin, raw corn starch or sucrose diets, whereas those fed either the lactose, fructose or cellulose diets had the lowest. Sturgeon fed either the maltose or glucose diets were hyperlipidemic, having twice the amount of plasma total lipid, triacylglycerol and total cholesterol as fish fed the other carbohydrate sources. These two carbohydrate sources were also more lipogenic: maltose- or glucose-fed sturgeon had significantly higher body lipid and liver G6PDH, malic enzyme, and ICDH activities. The poor ability of sturgeon to utilize either sucrose or lactose appears to be due to low intestinal sucrase (EC 3.2.1.48) and lactase (EC 3.2.1.108) activities. Intestinal aminopeptidase (EC 3.4.11.11), maltase (EC 3.2.1.20), sucrase and lactase activities of sturgeon were not affected by feeding different carbohydrate sources for 8 wk.
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PMID:Ability of juvenile white sturgeon (Acipenser transmontanus) to utilize different carbohydrate sources. 272 21

Animal experimentation with total parenteral nutrition (TPN) has revealed the occurrence of atrophy of the intestinal mucosa and decreased enzyme activities of the brush border, notably the disaccharidases. These findings have heretofore not been confirmed in human investigation. We performed endoscopic biopsies in the third part of the duodenum in 7 adults before TPN, after 21 days of TPN, and after a progressive oral refeeding. We noted a clear-cut decrease of major enzyme activities during TPN (sucrase, maltase, lactase, glucoamylase, acid aminopeptidase, dipeptidyl peptidase) without any morphologic modifications as observed with standard histology. Electron microscopy showed a slight but significant decrease in the height of microvilli. The decreased enzyme activities were rapidly restored after oral refeeding. Thus, the functional consequences of the modifications observed during medium-term TPN in adults are probably limited.
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PMID:Decreased brush border hydrolase activities without gross morphologic changes in human intestinal mucosa after prolonged total parenteral nutrition of adults. 307 17

To evaluate the response of the small intestinal mucosa to Saccharomyces boulardii (S.b.), a yeast widely used in some countries as an adjuvant drug with oral antimicrobial therapy, seven healthy adult volunteers were treated with high doses of lyophilized S.b. (250 mg four times per day) for 2 wk. A peroral jejunal suction biopsy was performed on days 0 and 15 of the study. Compared to the initial biopsy, histological examination of the posttrial biopsy revealed no morphological alteration nor change in villus height or crypt depth. After treatment, the specific activity (per U protein) of sucrase, lactase, and maltase was, respectively, increased by 82% (p less than 0.05) 77% (p less than 0.05), and 75% (p less than 0.05) over the basal activity of the enzymes measured on day 0, whereas mucosal protein content remained unchanged. Similar findings were found in the jejunum of adult rats treated for 5 days with either viable or killed S.b. cells. The changes in total enzyme activity (per jejunal segment) paralleled the changes in specific enzyme activity. In vitro assays on freshly prepared suspensions of S.b. (6.0 X 10(8) viable cells/ml) evidenced a high activity for sucrase (mean +/- SE: 8 364 +/- 1280 U X g X protein-1) but no maltase, neutral lactase, acid beta-galactosidase, or aminopeptidase activity. To determine whether treatment with S.b. could influence the incorporation rate of neutral lactase into the brush border membrane, 14-day-old sucklings treated either with saline or with S.b. were given intraperitoneally a dose of 20 microCi D-[1(14)C] glucosamine 3 hours before sacrifice.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Response of human and rat small intestinal mucosa to oral administration of Saccharomyces boulardii. 308 Jul 30

This investigation was undertaken to study the effects of hormones, sugars and amniotic fluid on the maturation of brush border enzymes in the human fetal intestine, at early stages of gestation. Intestinal explants from 8-13-weeks fetuses were maintained in organ culture for 3 days in the presence of the agents to be tested. The data show that the explanation of human fetal gut in a serum free culture medium elicits a significant maturation (2-4-fold increase above preculture levels) of lactase and aminopeptidase whatever the gestational stage studied and of sucrase and alkaline phosphatase at specific stages of development. To be expressed, the overall maturation needs the presence of sugar (in particular glucose) in the culture medium. The addition of dexamethasone, insulin or amniotic fluid to the medium did not further enhance brush border enzyme activities except for lactase whose levels were doubled by the dexamethasone. The present data suggest that in addition to the differences which exist among mammalian species in the timing of enzyme development, there may be a species specificity in the factors involved in fetal enzymatic maturation.
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PMID:Maturation of brush border hydrolases in human fetal intestine maintained in organ culture. 308 14

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.
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PMID:Effect of intravenous and intragastric fat infusion on intestinal brush border enzyme activities in rats. 308 1

A rapid and improved method to obtain purified lactase from rat intestine is described. The purification procedure involved only two chromatographic steps. The degree of purification was far above (500 fold) the values reached with classical methods. Rabbit antisera raised to the purified lactase were characterized using conventional immunological techniques. The specificity of the lactase antibodies was confirmed by the lack of interference on maltase, aminopeptidase and alkaline phosphatase activities measured after papain extraction of the membrane proteins.
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PMID:Improved purification of rat intestinal lactase. 309 77

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.
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PMID:Small-intestinal and colonic changes after biliopancreatic bypass for morbid obesity. 310 Nov 67

This study was designed to determine, on intestinal function, the comparative effects of a fat emulsion, a carbohydrate solution, and a mixture of lipids and carbohydrates given for 4 days to adult rats either intragastrically or intravenously. The rats were separated into three groups (n = 24 in each group). Each group was divided into two populations fed either intragastrically or intravenously. Each group received one of the following nutrients: a 20% Intralipid emulsion, a mixture (1:1, V/V) of Intralipid 20% and Vamine N containing 25% glucose (W/V), a solution of Vamine-glucose supplemented with fructose to reach a final concentration of 20% (W/V). Sham-operated rats that received laboratory chow orally were used as controls. The daily caloric intake was 0.21 to 0.22 kcal/g body weight. The studies on villus morphology and on brush border enzyme activities were performed on the proximal part of the jejunum. For all nutrients, intragastric infusion provoked an increase in the villus height. The lipids were the only nutrients to cause villus lengthening by the intravenous route. Intragastric or intravenous infusion of fat provoked a deficiency in intestinal disaccharidases; the presence of carbohydrates in the diet inhibited this effect slightly. Carbohydrates given alone, either intragastrically or intravenously, caused an elevation of lactase activity. Independent of diet composition, aminopeptidase activity was reduced after intravenous feeding. In conclusion, the disaccharidase activities are largely dependent on changes occurring in the nutrient composition given either intragastrically or intravenously, whereas amino-peptidase activity was related to the route of diet administration.
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PMID:A comparison of intestinal adaptation to short-term intravenous versus intragastric diet in adult rats. 311 30


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