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 assess the effect of dietary lactose on the intestinal absorption of protein, fat and calcium in lactose intolerance due to low levels of intestinal lactase, balance studies were carried out on postweaning rats (initial weight 164 g) for a period of 10 days. The experimental diets contained either 10% or 30% lactose, while in the control diets the lactose was replaced with equivalent amounts of sucrose. The excretions of fecal and urinary nitrogen, calcium and fat are expressed as precent of intake over the 10-day period. The fecal excretion of nitrogen and fat was significantly higher in the lactose groups (P less than 0.05). The fecal calcium excretion, however, was lower in the lactose groups, the difference being significantly only in the case of the 30% lactose diet (P less than 0.001). There was no difference in urinary nitrogen excretion between the lactose and sucrose groups, but urinary calcium excretion was significantly higher in the rats fed the 30% lactose diet (P less than 0.01). These findings suggest that dietary lactose may reduce the absorption of protein and fat, but not of calcium, in individuals with low levels of intestinal lactase activity.
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PMID:Effect of dietary lactose on the absorption of protein, fat and calcium in the postweaning rat. 111 21

1. The metabolic consequences of chronic ethanol feeding was investigated by assay of urinary metabolites. Male Wistar rats were fed a liquid diet containing 35% of total energy as ethanol or isovolumetric, isocaloric and isonitrogenous amounts of the same diet in which ethanol was substituted by isocaloric glucose (controls). 2. At 6 weeks the entire skeletal muscle mass was reduced by approximately 20%. The urinary excretion of nitrogen, urea and uric acid increased by between 23 and 128%. Urinary creatinine excretion was not significantly altered. 3. Urinary excretion of magnesium was significantly increased by 43%. Urinary excretion of sodium, potassium, calcium and phosphate was increased slightly (i.e. 5-22%), but this change was not statistically significant. 4. Proton n.m.r. spectroscopic analysis showed that ethanol feeding reduced the urinary excretion of citrate and 2-oxoglutarate (by approximately 50%), suggesting decreased citric acid cycle activity. There was an increased excretion of alanine (44%), but excretion of succinate and acetate was not significantly altered. Ethanol in the urine of ethanol-fed rats comprised approximately 2% of total ethanol intake and less than 1% of total energy intake. 5. Lactose was detectable in urine of ethanol-fed rats, but not in control rats, reflecting the reported decreased intestinal lactase activity and increased gut permeability in alcoholics. Urinary galactose excretion decreased by 41%, but relatively large increases in lactate excretion (50%) did not achieve statistical significance. 6. It was concluded that chronic ethanol feeding causes disturbances in whole-body nitrogen homoeostasis and alterations in intermediary metabolism.
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PMID:Urinary excretion of nitrogenous and non-nitrogenous compounds in the chronic ethanol-fed rat. 185 Oct 76

Gastric intubation was adopted as a means of comparing the effect of two feeding levels, continuous nutrient supply (C) and restricted nutrient supply (R), on the digestive development of pigs weaned at 14 d of age, during the first 5 d post-weaning. The absolute weights of the stomach and the pancreas were significantly greater (P less than 0.001) in C compared with R pigs. The effect was not significant for pancreas weight when expressed per kg body-weight but was significant (P less than 0.05) for stomach weight. The weights of the small intestine (SI), SI mucosa and total mucosal protein were significantly higher (P less than 0.001) in C pigs but protein content per g mucosa was similar in the C and R groups. There was no significant effect of treatment on the activity of lactase (beta-glucosidase; EC 3.2.1.23) or sucrase (sucrose-alpha-glucosidase; EC 3.2.1.48) irrespective of the basis of comparison used. The specific activity (mumol/min per g protein) of maltase (alpha-glucosidase; EC 3.2.1.20) and of glucoamylase (glucan-1,4-alpha-glucosidase; EC 3.2.1.3) were similar in C and R groups but activities of maltase (mumol/g mucosa) (P less than 0.05), and maltase and glucoamylase (mol/d) (P less than 0.01) were significantly higher in C pigs. Villous height and crypt depth were significantly greater in C pigs (P less than 0.001 and P less than 0.05 respectively). Enteroglucagon was significantly (P less than 0.05) higher in C compared with R pigs. Xylose absorption and the digestibility of energy were not affected by treatment. Digestibility of dry matter, organic matter, crude protein (nitrogen x 6.25) and carbohydrate were significantly higher (P less than 0.001, P less than 0.01, P less than 0.05 and P less than 0.001 respectively) in R pigs compared with C pigs but the differences were small, ranging from 1.3 to 2.5%. These results demonstrate that (1) nutrient intake in the weaned pig affects the anatomy, morphology and function of the gut, (2) there is considerable 'spare capacity' for digestion of cereal-based diets even in pigs weaned at 14 d of age, (3) measurements in vitro of digestive function are of limited value unless supported by information in vivo on absorption/digestibility.
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PMID:Digestive development of the early-weaned pig. 2. Effect of level of food intake on digestive enzyme activity during the immediate post-weaning period. 204 2

Gut atrophy develops during prolonged total parenteral nutrition (TPN). TPN solutions do not contain glutamine, an energy substrate of the intestinal tract. This study evaluated the effect of addition of L-glutamine to TPN on gut nitrogen content, histology, and disaccharidase enzyme activity. Five groups of six Fisher 344 rats received rat chow, D5W, TPN (23% calories as lipid), or TPN with 1 or 2% L-glutamine. Animals given TPN received 30 kcal and 0.22 g nitrogen/100 g/day. Metabolic cages allowed nitrogen balance for each group. After 6 days infusion, stomach, small bowel, and colon were assayed for total nitrogen and sucrase, lactase, and maltase activity. Mucosal height and fatty infiltration of the liver were determined from histologic sections. Adding either 1 or 2% L-glutamine resulted in no toxic clinical effects. Glutamine preserved intestinal nitrogen content of the stomach and colon compared to standard TPN and increased nitrogen content of small bowel to greater than that in chow-fed animals. Glutamine maintained mucosal height of the stomach and colon, but was no better than TPN alone in maintenance of small bowel mucosal height. One percent glutamine increased and standard TPN depressed maltase activity compared to chow. Standard TPN and 1% glutamine both stimulated sucrase and lactase activity compared to chow. Addition of 1 or 2% glutamine protected the liver from fatty infiltration seen with standard TPN. These studies would suggest the addition of glutamine might be beneficial during provision of standard total parenteral nutrition.
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PMID:Use of L-glutamine in total parenteral nutrition. 313 88

Protein, fat and carbohydrate absorption in preterm infants fed on human milk or formulae are reviewed. Even in the most premature infants absorption of protein is satisfactory. Nitrogen net absorption is about 85-90% of intake and results slightly lower with human milk than with formulae. The lower apparent digestibility of human milk is probably due to the poorly degraded IgA immunoglobulins and the rapid transit time. Lactose is well tolerated by the preterm infants despite the low lactase activity at birth. Glucose polymers, which have a low osmotic activity and are suitable for increasing carbohydrate intake of formulae, are well absorbed probably for the activity of salivary amylase and brush border glucoamylase, which have been shown to be well developed at birth. Premature infants absorb fat poorly. This malabsorption that increases with the lowering of gestational age is due to low pancreatic lipase activity and to low intraluminal concentration of bile salts. Due to its bile stimulated lipase activity, non-heat-treated human milk used at least in part is an effective method to improve fat absorption in preterm infants. Faecal energy determined using a calorimetric bomb appears to be a simple and an accurate method to predict faecal fat and avoiding expensive and cumbersome analysis.
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PMID:[Absorption of proteins, carbohydrates and fats in the preterm neonate]. 357 19

Seventy-two hour starvation in neonatal rabbits was studied. Fasted animals received no feeds, only water every 8 h for 72 h. Fed animals were suckled by the dam. There was no difference in birth weight, serum albumin, blood urea nitrogen, electrolytes, or urine specific gravity between fed and fasted animals. Weight at 72 hr was less in fasted (p less than 0.01) than fed rabbits. Serum cortisol (p less than 0.05) and corticosterone (p less than 0.01) levels were higher in the fasted group. Proximal and distal small bowel homogenates had less DNA and protein (p less than 0.01) in the fasted group, but the protein/DNA ratio was the same in the proximal and distal small bowel homogenates from both groups. Sucrase (E.C.3.2.1.26) specific activity was significantly increased in proximal small bowel homogenates from the fasted group (p less than 0.01) but was the same in distal small bowel homogenates from both groups. Sucrase total activity per proximal segment was the same in fed and fasted animals but was significantly less per segment in distal small bowel homogenates from fasted animals. Alkaline phosphatase (E.C.3.1.3) total and specific activity was decreased in proximal (p less than 0.01) and distal (p less than 0.05) small bowel homogenates from the fasted group. Lactase (E.C.3.2.1.23) total activity was decreased in proximal and distal (p less than 0.01) small bowel homogenates from the fasted group but lactase specific activity was unchanged. Thus, a brief period of malnutrition in neonatal animals can result in a variety of regional functional changes in the gastrointestinal mucosa.
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PMID:Short-term malnutrition in neonatal rabbits. I. Brush border enzymes. 368 82

Seven pyranoses and three furanoses with a nitrogen in the ring were prepared by chemical synthesis, microbial conversion, and isolation from plants to investigate the contribution of epimerization, deoxygenation, and conformation to the potency of inhibition and specificity of mammalian glycosidases. The seven pyranoses are 1-deoxynojirimycin (1), the D-manno (2), D-allo (3), and D-galacto (4) isomers of 1, fagomine (1,2-dideoxynojirimycin, 5), and the D-allo (6) and D-galacto (7) isomers of 5, while the three furanoses are 2,5-dideoxy-2,5-imino-D-mannitol (8), 1,4-dideoxy-1,4-imino-D-arabinitol (9), and 1,4-dideoxy-1,4-imino-D-ribitol (10). The 2-deoxygenation and/or 3-epimerization of 1 enhanced the potency for rat intestinal lactase and bovine liver cytosolic beta-galactosidase. Especially compound 6 showed a potent inhibitory activity against both enzymes, and compound 8, a mimic of beta-D-fructofuranose, was a potent inhibitor of both beta-galactosidases as well. Compound 4, which has been known as a powerful alpha-galactosidase inhibitor, exhibited no significant inhibitory activity for most of mammalian beta-galactosidases. In addition, compound 6 fairly retained a potency of 1 toward rat intestinal isomaltase. In this study, compound 8, known as a processing alpha-glucosidase I inhibitor in cell culture, has been found to have no effect on processing alpha-glucosidase II, whereas 9 has been shown to be a good nonspecific inhibitor of intestinal isomaltase, processing alpha-glucosidase II, Golgi alpha-mannosidases I and II, and porcine kidney trehalase. It has been speculated that glycosidase inhibitors have structures which resemble those of the respective glycosyl cations. This Broad inhibitory activity of 9 toward various glycosidases suggest that it superimposes well on the various glycosyl cations.
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PMID:Nitrogen-in-the-ring pyranoses and furanoses: structural basis of inhibition of mammalian glycosidases. 796 30

The aim of this study was to evaluate the effect of two sources of dietary nitrogen (isolated whey protein and hydrolyzed whey protein) on the intestinal repair of malnourished rats at weaning. The malnutrition was achieved by a 3 days' starvation period. Normally fed male Wistar rats were used as controls. Intestinal repair was studied after a refeeding period of 4 days. The parameters studied included nitrogen balance, lactase, sucrase, isomaltase, and maltase activities of the jejunum; liver acetylcholinesterase and glutamate dehydrogenase activities; and the serum amino acid profile. In addition, tests of intestinal permeability to macromolecules were performed by measurement of ovalbumin and beta-lactoglobulin in serum. Both diets of led to the recovery of the severely starved rats, in terms of the values of all the parameters evaluated. The serum beta-lactoglobulin was the only exception, because its concentration was significantly lower in the normally fed animals. This study suggests that the intestinal mucosal barrier is not completely repaired, even after a 4-day refeeding period, to the point of being suitable to accept an increase in the uptake of antigens.
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PMID:Effects of native and hydrolyzed whey protein on intestinal repair of severely starved rats at weaning. 864 92

Factors affecting the beta-galactosidase production by Penicillium notatum 1 were studied using fermentation media of different chemical composition. The medium containing lactose, salts, peptone and yeast extract with initial pH 2.5 was selected as the best for enzyme production. Monobasic ammonium phosphate (0.9%) was found to be the best inorganic nitrogen source for lactase production. Various extraction media and metabolic inhibitors were examined for effective releasing of beta-galactosidase from the fungal cells. Using a simple method of mycelium extraction with 0.1 Triton X-100, it was possible to obtain about 4-fold higher amounts of enzyme in the cell free extracts, than those excreted into the post-culture liquid.
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PMID:Effect of medium components and metabolic inhibitors on beta-galactosidase production and secretion by Penicillium notatum 1. 881 42

A study was undertaken to assess the impact of the protein nature and soya antigenicity on the morphology and some enzyme activities of the jejunum in preruminant calves. Twenty Holstein calves fitted with a duodenal cannula were fed a liquid diet based on skimmed milk powder (SMP) for 2 weeks. They were then switched onto diets containing a mixture of SMP and either antigenic heated soybean flour (HSF; n = 12) or hypo-antigenic soya protein concentrate (SPC; n = 8) for 8 weeks, after which they were reverted back to the SMP diet for 2 weeks. The diets contained similar amounts of digestible nitrogen and energy, and were fed at a rate of 55 g DM/kg(0.75)/d. Proximal jejunal biopsies were collected just before (week 0), during (weeks 2 and 8) and after (week 10) feeding of the soya-based diets, and were used for morphology measurements and the determination of total alkaline phosphatase, lactase, amino-peptidases A and N, and dipeptidyl peptidase IV activities. Feed intake and growth were similar between the HSF and SPC groups during the experimental period. The effects of antigenicity and the antigenicity x time interaction were never significant (P > 0.05). Villus height decreased (P < 0.01) between weeks 0 and 2, and increased (P < 0.05) between weeks 8 and 10. Villus width increased between weeks 2 and 8 (P < 0.001). Crypt depth also increased between weeks 0 and 2 (P < 0.001). Specific activities of alkaline phosphatase (P < 0.01) and amino-peptidase N (P < 0.05) decreased between weeks 0 and 2. Conversely, those of alkaline phosphatase (P < 0.0001), lactase (P < 0.01) and dipeptidyl-peptidase IV (P < 0.0001) increased between weeks 8 and 10. Specific activities for lactase and amino-peptidase N decreased (P < 0.01) between weeks 2 and 8. The treatments had little effects on the amino-peptidase A activity. In conclusion, the present work demonstrated that soybean protein markedly depressed the morphology and most enzyme activities of the calf small intestine. On the contrary, the in vitro antigenicity of soybean protein had little influence on these parameters in this study.
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PMID:Morphology and enzyme activities of the small intestine are modulated by dietary protein source in the preruminant calf. 1049 51


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