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)

Brush border sucrase and lactase activities are significantly elevated in alloxan-induced chronic diabetes and are restored to control levels after insulin treatment. Alkaline phosphatase and Mg-ATPase levels remain unchanged in diabetes, compared to a control group. Insulin treatment alone to control animals also led to enhanced activities of these enzymes.
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PMID:Effect of chronic alloxan diabetes and insulin administration on intestinal brush border enzymes. 14 19

It was taken 32 male Wistar rats, weighting between 130 g and 150 g, free feeding, to study the total and specific activities of lactase, invertase and maltase of small intestine of rats. The animals were divided by chance in 3 experimental and 1 control group. 1. group--Aloxanic diabetes rats: treated with 1 unit of NPH insulin every day: after the 4th day of aloxane administration, all rats were killed. 2. group--Aloxanic diabetes rats--treated for 5 days with 1 unit of NPH insulin every day; after the 5th day until the 7th they were treated with 4 units of NPH insulin and were also killed. 3. group--Hyperinsulinism rats--Normal rats were treated for 4 days with 4 units of NPH insulin every day. After the 5th day they were killed. 4. group--Control group--Normal rats, free feeding. They were observed during 4 days and were also killed. The results showed that none difference was observed in the 4 groups of rats about the total and specific activities of lactase, invertase and maltase of the small intestine. In this study, all the animals with aloxanic diabetes were treated with insulin. Then, it is possible that the insulin inhibited the stimulator effect of the diabetes upon the dissacaridases of the small intestine of the rats.
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PMID:[Insulin and disaccharidases levels of the small intestine of the rat (author's transl)]. 74 51

Digestive enzymatic activities (disaccharidases, alkaline phosphatase, peptide hydrolases) have been determined in the mucosa of 14 patients with chronic pancreatitis. All had an abnormal secretin-pancreozymin test. Four patients had insulin-dependent diabetes mellitus, four a pathological glucose tolerance test. Nine patients had steatorrhoea. Maltase, sucrase, and alkaline phosphatase activity was significantly elevated in patients with exocrine pancreatic insufficiency, whereas those of lactase, trehalase, and peptide hydrolase were normal. Patients with steatorrhoea had higher maltase and sucrase activity than those without steatorrhoea, whereas decreased glucose tolerance had no effect on brush border enzymatic activity. It is suggested thatdecreased exocrine rather than decreased endocrine pancreatic function is responsible for the increase in intestinal disaccharidase and alkaline phosphatase activity, possible by the influence of pacreatic enzymes on the turnover of brush border enzymes from the luminal side of the mucosal membranes or by direct hormonal stimulation though cholecystokinin.
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PMID:Influence of exocrine and endocrine pancreatic function on intestinal brush border enaymatic activities. 109 2

The standard lactose tolerance test involves measuring a patient's blood glucose after the ingestion of lactose. If the patient has lactase deficiency and is unable to hydrolyze lactose and absorb its monosaccharides, glucose and galactose, the blood glucose does not usually increase greater than 20 mg/100 ml. Since factors other than the absorption of glucose can cause an increase in the blood glucose of greater than 20 mg/100 ml in a diabetic, this test could be unreliable when it is performed on a diabetic. The present study was performed to determine whether the lactose-ethanol tolerance test could be used to diagnose lactoase deficiency in diabetics. This test involves measuring the blood galactase level, instead of the blood glucose, and the administration of ethyl alcohol to a subject prior to the test to delay the clearance of galactose from the circulation. The results indicate that the standard lactose tolerance test in which the blood glucose is measured is unreliable when performed on insulin-dependent diabetics, but that it can be reliable when performed on non-insulin-dependent diabetics. The lactose-ethanol tolerance test gave results in each type of diabetic which were qualitatively similar to those of nondiabetics. It was concluded that the latter test is a useful screening test for lactase deficiency in diabetics.
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PMID:Use of the lactose-ethanol tolerance test in diabetes. 114 47

The small intestinal disaccharidase activity and its daily variation in the diabetic rat have not been well described. Therefore, the small intestinal disaccharidase (maltase, lactase and sucrase) activity and its daily profile were studied in streptozotocin-induced diabetic rats under physiological conditions. In diabetic rats, a similar pattern of diurnal variation of disaccharidase activity to control rats was observed, while the relationships between daily change of disaccharidase activity and that of food consumption suggested that there was a different mechanism of diurnal variation in diabetic rats. On the other hand, a significant increase of mean 24-h lactase and sucrase activities was noted in diabetic rats, while that of maltase was not significant. Using the in vitro incubation method, a significant correlation between glucose concentration and lactase or sucrase activity but not maltase activity was observed. However, insulin showed no effect on disaccharidase activity. Thus we clarified the presence of a diurnal variation of disaccharidase activity and an increase in its activity in diabetic rats. This change was suggested to be derived from high plasma glucose level.
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PMID:Diurnal variation and increase of disaccharidase activity in diabetic rats. 145 37

Insulin, found in human and pig colostrum and mature milk, appears to influence small intestinal growth and development. Ileal lactase activity is increased when porcine insulin is added to feedings administered to newborn piglets. We studied 2-day-old miniature piglets to determine whether the increase in lactase activity is accompanied by changes in enterocyte expression of lactase activity, steady-state levels of lactase mRNA, and/or posttranscriptional changes in lactase processing. We randomized the piglets to receive bottle feedings of a swine-weaning milk formula with (group F + I) or without (group F) the addition of 85 mU/ml of regular porcine insulin. The piglets were fed for 6 days (to 8 days of age), after which they were killed and the small intestine removed for analysis. Despite large differences between groups in enterocyte expression of lactase activity in the ileum, no differences were noted in the level of ileal lactase mRNA. The relative proportions of the 207, 210, and 230 kDa precursors of the 160 kDa mature lactase protein were similar between groups. These data indicate that the insulin-induced increased expression of ileal lactase activity is not regulated at the level of its mRNA or at the level of processing of the polypeptide.
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PMID:Effect of oral insulin on lactase activity, mRNA, and posttranscriptional processing in the newborn pig. 159 71

Factors, such as insulin, found in human and pig colostrum and mature milk likely influence small intestinal growth and development. Although pharmacologic doses of insulin injected parenterally may accelerate small intestinal development in altricial animals such as the rodent, the effects of oral insulin on intestinal development have not been studied. In the first of two studies, we randomized 2-d-old miniature piglets to receive bottle-feedings of a swine weaning milk formula with (group F + I) or without (group F) the addition of insulin. Serum glucose, insulin, and cortisol were measured before and 1 h after the first feeding the piglets received at our facility. In the second study, piglets were randomized (groups F and F + I) and fed for 6 d, after which blood samples were obtained as in the first experiment. The piglets were then killed and the small intestine removed for analysis. We found no differences between groups in serum glucose, insulin, and cortisol at both 2 and 8 d of age, both before and after feeding. In the second experiment, small intestinal weight was greater in the F + I than in the F group. Although no differences were noted between groups in the jejunum, values were greater for group F + I versus group F for ileal mucosal weight, protein, RNA, lactase, and maltase activities. No differences were found between groups in ileal DNA or sucrase activity. We conclude that the administration of oral insulin stimulated an increase in ileal mass and disaccharidase activity in the newborn miniature pig without apparent concomitant changes in serum glucose, insulin, or cortisol.
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PMID:Oral insulin increases small intestinal mass and disaccharidase activity in the newborn miniature pig. 169 70

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

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

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


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