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

Activities of lactase and sucrase were determined in proximal, middle, and distal thirds of the jejunoileum of 15-wk-old male rats starved for 1, 2, and 3 days and in rats fed a high-sucrose diet for 24 h after 3 days of starvation. Sucrase activity (expressed per tissue protein or DNA as well as per intestinal segment) showed a progressive decrease during starvation in proximal and middle segments but not in the distal segment. Lactase activity expressed per tissue protein or DNA in all segments increased significantly. This was obviously due to the loss of tissue protein and DNA because total lactase activity per segment did not change. Refeeding the sucrose diet produced an increase of sucrase activity without influencing lactase activity. In serial tissue homogenate of jejunal villus-crypt columns prepared using cryostat sectioning, it was shown that, during starvation, activity of lactase (specific and total) increased in the upper and middle villus. Sucrase activity (specific and total) during starvation decreased and after refeeding increased in the lower and middle villus.
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PMID:Different effect of starvation on activity of sucrase and lactase in rat jejunoileum. 640 78

In the adult rat, starvation during 48 hours led to a three fold increase of lactase specific activity in the intestinal brush border membranes. Thyroxine injection during the three days before death (0.5 micrograms/g daily) inhibited the stimulation of lactase activity induced by starvation without modifying sucrase activity whereas hydrocortisone injections (25 micrograms/g daily) or thyroidectomy did not modify the stimulatory effect of starvation on lactase activity. These results suggests a specific hormonal control of intestinal lactase activity in the rat.
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PMID:Lactase activity is under hormonal control in the intestine of adult rat. 640 6

We have studied the action of sucrose on jejunal sucrase activity. Rats (175 g) were first starved or fed a digestible carbohydrate-free diet for 60 h and then fed a high sucrose diet for varying times up to 84 h. 1) Rats starved for 60 h showed mucosal atrophy with a decrease in protein content/10 cm (18.00 +/- 1.4 versus 40.1 +/- 3 mg (controls p less than 0.001) and in villus height (357 +/- 18 versus 526 +/- 5 microns, p less than 0.001) which was fully repaired only after 60 h on the sucrose diet (528 +/- 11 microns). Rats on digestible carbohydrate-free diet showed no mucosal atrophy. 2) Starved rats had a delayed (60 h) sucrase activity response to sucrose (53 +/- 7 versus 122 +/- 4 microns/mg protein, p less than 0.001). Maximum activity was obtained after 12 h on sucrose diet in rats maintained on the carbohydrate-free diet: 38 +/- 1 versus 108 +/- 2.3 microns/mg protein, p less than 0.001. 3) Villus and crypt cell analysis after starvation and 12 h on a high sucrose diet localized the increase in sucrase activity to the villus-crypt junction. No change occurred in the upper villus. The increase was complete all along the villus by 36 h. In contrast, after the carbohydrate-free diet, sucrase activity increased maximally at all levels of the villus by 12 h on the high sucrose diet.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Influence of starvation on sucrase regulation by dietary sucrose in the rat. 649 81

The effect of jejunal sucrase activity of premature weaning (PW) of rats is studied and compared with the effect of starvation. Within 24 hours after PW of rats on postnatal day 16 onto a high sucrose diet, there is a highly significant increase in sucrase activity as compared with that in nonseparated controls. During this time, food intake is minimal, the rats lose weight and there is an arrest of jejunal growth. Rats starved from day 16 onward exhibit the same increase of sucrase activity. Adrenalectomy on day 14, i.e. 2 days before PW, results in 33% mortality on the second postweaning day, i.e. on day 18, and in progressive loss of jejunal protein. Sucrase activity in adrenalectomized prematurely-weaned rats does not differ from the activity of intact suckling controls on day 18. Our experiments suggest that the increase in sucrase activity following PW is not related to food intake, but is primarily mediatd by the adrenal glands. Presented results stress the importance of the endocrine system in the intestinal "adaptive" response to PW in the rat. Endocrine factors should be considered in any evaluation of the effect of nutritional manipulation during the weaning period.
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PMID:Critical role of adrenal glands in precocious increase in jejunal sucrase activity following premature weaning in rats: negligible effect of food intake. 676

The circadian rhythm of the activities of maltase and sucrase of the small intestine were examined in rats kept under conditions of continuous lighting with various fixed feeding periodicities for 20 days. When rats were fed once every 24 h, the enzymes showed circadian rhythmic changes with high activities around the feeding time, and the enzyme rhythm persisted even during subsequent starvation. Similar rhythmic changes in the enzyme activities were found in rats fed once every 48 h. When rats were fed once every 32 h, the enzymes showed rhythmic changes with a period of 32 h, but the activities were lowest during the feeding time. The enzyme rhythm with a period of 32 h was replaced by a 24-h circadian rhythm as soon as the rats were starved. It was concluded that the circadian rhythmic changes in disaccharidase activities are controlled by an endogenous mechanism, and that some circadian time-keeping system participates in this mechanism.
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PMID:Circadian rhythm of intestinal disaccharidases of rats fed with adiurnal periodicity. 698

The activities of microvillus aminopeptidase (microsomal, EC 3.4.11.2), dipeptidyl peptidase IV (EC 3.4.14.-), glycyl-leucine dipeptidase (EC 3.4.13.11), proline dipeptidase (EC 3.4.13.9), sucrase (EC 3.2.1.48) and gamma-glutamyl transpeptidase (EC 2.3.2.2) were measured in peroral intestinal biopsies taken from patients with coeliac disease in the acute phase and in remission. A comparison with the amounts of corresponding activities from a reference group showed that all the measured activities were significantly decreased in the acute phase of the disease. In patients in remission only microvillus aminopeptidase and dipeptidyl dipeptidase IV displayed a substantial depression as compared to the reference group. It is suggested that a primary mucosal digestion defect will result in lack of substrate for other intestinal enzymes. This is a situation comparable to starvation and may explain the variation in the grade of restitution for the different enzymes.
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PMID:Intestinal peptidases and sucrase in coeliac disease. 700 82

The effect of resuming food intake after a period of starvation (refeeding) on the specific activities of selected rat intestinal enzymes was determined. The rate of weight gain was higher in refed animals than in control animals, without a difference in food intake. Fasting caused intestinal atrophy which reversed rapidly on refeeding. Fasting decreased the specific activities of sucrase, maltase, and galactokinase, but did not affect the specific activities of hexokinase, pyruvate kinase, or crypt thymidine kinase. Sucrase, maltase, hexokinase, pyruvate kinase, and thymidine kinase specific activities all rose above control values during refeeding. The overshoot in intestinal enzyme specific activities may help promote the rapid weight gain observed in refed rats and is an integral part of the total adaptation to fasting and refeeding.
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PMID:Refeeding after a fast in rats: effects on small intestinal enzymes. 705 2

Aminopeptidase, lactase and sucrase activities have been followed during 5 days in the jejunum and in the ileum of starved adult rats. Enzyme activities have been determined in the mucosal homogenates as well as in the purified brush border membranes and expressed as activities per intestinal length (segmental activities) or as activities per milligram of protein (specific activities). The segmental and specific activity of aminopeptidase was increased in the ileum during the first 2 days of starvation, suggesting that aminopeptidase may have during the first days of starvation a conservative role by preventing an important loss of tissue protein. In all conditions, lactase activity was strikingly enhanced by starvation whereas sucrase activity showed no changes or decreased activity. Lactase stimulation was initiated during the first 24 h of starvation reaching its maximum after 2 days. The various experimental conditions leading to a specific or to a nonspecific stimulation of intestinal lactase activity have been discussed.
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PMID:Modifications of brush border enzyme activities during starvation in the jejunum and ileum of adult rats. 715 74

Addition of glucose to cells of the yeast Saccharomyces cerevisiae growing on a nonfermentable carbon source triggers a rapid, transient increase in the cAMP level. The occurrence of this cAMP spike appears to be correlated inversely with the glucose-repression state of the cells. This was also observed for the hex2 mutant, which is deficient in glucose repression and which displayed the cAMP signal constitutively. When cells of the hex2 mutant were starved for nitrogen on a glucose-containing medium, they rapidly lost viability, similarly to mutants with overactivation of the Ras-adenylate cyclase pathway. Flow cytometry measurements showed that G1 arrest of the hex2 mutant under such conditions was incomplete. Trehalose accumulation, a typical feature of cells entering the stationary phase G0, was very short-lived in the hex2 mutant under the same conditions. These results are in agreement with the presence of continuous glucose-triggered activation of cAMP synthesis in hex2 cells on a glucose-containing nitrogen-starvation medium. In the course of these experiments a spontaneous suppressor mutant, shx (for suppressor of hex2), was isolated which survived nitrogen starvation on a glucose-containing medium much better than the hex2 strain. It also showed normal G1 arrest and much longer accumulation of trehalose. The suppressor mutation also caused inability to grow on nonfermentable carbon sources and absence of invertase depression, and it was epistatic to hex2 for these characteristics also. The isolation of this epistatic depression mutation supports the idea that the defect in glucose repression of the hex2 mutant is the cause of its rapid loss of viability during nitrogen starvation on a glucose-containing medium.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Constitutive glucose-induced activation of the Ras-cAMP pathway and aberrant stationary-phase entry on a glucose-containing medium in the Saccharomyces cerevisiae glucose-repression mutant hex2. 755 Oct 24

The effect of starvation and refeeding on the developmental pattern of intestinal sucrase-isomaltase (SI) was analyzed in preweaned rats. Starvation at postnatal day 12 caused a precocious expression of SI activity and mRNA. Alkaline phosphatase activity was slightly reduced, and no significant change was observed for aminopeptidase and lactase activities. Immunostaining showed that SI molecules appear in cells at the base of the villus. Sucrase expression was further increased by prolonged food deprivation, whereas enzyme activity as well as the amount of SI mRNA dropped to reach the low level found in control sucklings when 48 h-starved pups were refed by returning them to their dams. During the refeeding period, the enterocytes that were committed to produce SI by starvation continued to express the enzyme while migrating up the villi. However, the new epithelial cells arising from the crypts no longer synthesized the disaccharidase. The starvation-evoked appearance of SI was preceded by a transient burst of expression of the protooncogene c-fos, an event that may be correlated to the ontogenic rise of c-fos mRNA observed before weaning. However, in contrast to the normal weaning condition, SI induction by starvation occurred without obvious increase of epithelial cell proliferation and turnover. During the starvation and refeeding period, patterns of sucrase activity and SI mRNA paralleled the serum level of glucocorticoids.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Precocious and reversible expression of sucrase-isomaltase unrelated to intestinal cell turnover. 817 95


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