Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cells were isolated by sequential collagenase digestion from the parietal segments of one day old mice (Swiss albino BNL strain) and characterized for osteoblast parameters by alkaline phosphatase histochemistry and bovine parathyroid hormone (bPTH-(1-34] induced cAMP activity (protein binding assay). Phenytoin (DPH) reduced PTH stimulated cAMP activity nearly 3-fold in the presence and nearly 1.5-fold in the absence of added calcium. In the absence of PTH, DPH exerted no significant effect. Bay-K-8644, a calcium channel activator, appeared to approximate the PTH stimulation of cAMP activity, even in the presence of DPH. This study demonstrates that DPH has a direct effect on PTH stimulated cAMP activity in cultured murine osteoblasts.
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PMID:The effect of phenytoin on parathyroid hormone stimulated cAMP activity in cultured murine osteoblasts. 215 57

Phenytoin (PHT), a widely used anticonvulsant, has been shown to inhibit bone resorption in rodent organ cultures. The drug also has complex effects on bone metabolism including chronic clinical symptoms of osteomalacia. However, the precise mechanism of PHT action in bone is still unclear. Neutral collagenases that specifically cleave native collagen have been implicated in the turnover of connective tissue. The effect of PHT was assessed on collagenase and gelatinase activities from UMR 106-01 rat osteoblastic osteosarcoma cells. Semiconfluent cells were treated with PHT (50 and 10 micrograms/ml) in the presence of bovine parathyroid hormone, b-PTH-(1-34), at 10(-7) M for 24, 48, 72 and 96 h. The media were assayed following concentration, APMA activation, and incubation with native or denatured [3H]-methyl collagen substrate (approximately 100,000 dpm) at 27 degrees C for 18 h and 35 degrees C for 2 h, respectively. Enzyme activities were presented as primary counts per minute for each time point and calculated as % activity of PTH at 10(-7) M. Parathyroid hormone (10(-7) M) stimulated collagenase activity (approximately 65-fold) and gelatinase activity (approximately 400-fold). PHT (50 micrograms/ml) reduced the PTH-stimulated collagenase activity by 18-53% and the gelatinase activity by 58-72%. SDS PAGE and fluorography following PHT treatment indicated a PHT-induced partial inhibition of PTH-stimulated degradation to alpha A chains of Type I collagen. Phenytoin may inhibit bone resorption through its action on the transcription, synthesis, and/or secretion of the collagenolytic enzymes, collagenase and gelatinase.
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PMID:The effect of phenytoin on collagenase and gelatinase activities in UMR 106-01 rat osteoblastic osteosarcoma cells. 216 99

Phenytoin has been proposed for the treatment of certain dermatologic conditions involving connective tissue abnormalities. To understand the biochemical basis of connective tissue changes, we incubated human skin fibroblasts in culture with varying concentrations of phenytoin. The results indicated that fibroblast proliferation, detected by tritiated thymidine incorporation into cells, was slightly stimulated when short incubation periods and low concentrations of phenytoin were employed. However, with longer incubation times and higher phenytoin concentrations, a significant reduction in fibroblast proliferation was observed. Further studies demonstrated that incubation of cells with phenytoin did not affect the production of procollagen, measured as synthesis of radioactive hydroxyproline in the cultures. However, assay of prolyl hydroxylase, an enzyme participating in the post-translational synthesis of hydroxyproline during collagen biosynthesis, was significantly reduced in the fibroblast cultures. The activity of collagenase, an enzyme participating in degradation of collagen, was markedly decreased in cultures treated with phenytoin. Thus, phenytoin may modulate collagen metabolism primarily by affecting the degradation of collagen. The results support previous suggestions that phenytoin may be useful for treatment of patients with increased levels of collagenase, such as in recessive dystrophic epidermolysis bullosa.
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PMID:Phenytoin modulates connective tissue metabolism and cell proliferation in human skin fibroblast cultures. 298 18

The influence of sex and age on membrane fluidity, has been investigated in 6, 12, 18 weeks old Sprague-Dawley rats. Fluorescence polarization (P) was determined at 37 degrees C with a Perkin Elmer MPF 44A fluorescence spectrophotometer. The fluorescent probe TMA-DPH was added to isolated hepatocytes prepared by collagenase method. The membrane fluidity was constantly lower in males than in females, but the difference was statistically significant only in the 12 weeks old group. Major differences appeared related to aging with a significant age-related decrease in fluidity in all animals.
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PMID:Age and sex related changes of plasma membrane fluidity in isolated rat hepatocytes. 319 Jun 83

The dynamics of membrane microstructure was studied as molecular motions of phospholipids for bullfrog erythrocyte ghosts by the DPH fluorescence depolarization technique with a nanosecond fluorometer. The bullfrog erythrocyte ghosts were obtained by hypotonic lysis and collagenase treatment. The constituents of membrane proteins were confirmed by the disk gel electrophoresis. The viscosity of erythrocyte membrane ghosts was estimated to be 3.3 +/- 1.0 at 10 degrees C, and 2.1 +/- 0.1 at 20 degrees C and 1.3 +/- 0.2 at 30 degrees C in the unit of poise and the wobbling angle of lipid molecule was 35 +/- 1, 41 +/- 1 and 43 +/- 1 degree at the respective temperatures on an average and +/- S.D. The viscosity is lower than that of human erythrocytes. The relatively low viscous phospholipid bilayer may be one of the factors for the deformability of bullfrog erythrocytes.
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PMID:Dynamics of membrane structure of frog erythrocyte ghosts measured with a nanosecond fluorometer. 366 92

Stenosis or complete occlusion of the oesophagus are potentially life-threatening complications of recessive dystrophic epidermolysis bullosa. Consequences are malnutrition, growth retardation, aspiration, or cachexia. Total replacement of the oesophagus by colon interposition has been recommended in such patients. We report on successful conservative management. We applied recently developed knowledge concerning the defective collagenase involved in this disorder and oesophageal dilatation. Phenytoin has been shown to reduce the excessive production of collagenase and thereby to diminish blistering of skin and mucous membranes and stricture formation of the oesophagus. Stepwise dilatation of oesophageal strictures instead of bouginage represents a less traumatic way to restore the oesophageal lumen. The lumen can be maintained by soft nasogastric feeding tubes which may be removed later on after successful dilatation. Oesophageal passage has been maintained for up to 4 years. The management of these severe complications of recessive dystrophic epidermolysis bullosa requires interdisciplinary efforts of dermatologists, internists and otorhinolaryngologists.
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PMID:[Therapy of esophageal stenoses in recessive epidermolysis bullosa dystrophica]. 406 56

1. Phenytoin was intraperitoneally injected in six different experimental groups of adult Mongolian gerbils of both sexes at doses of 5, 100 and 150 mg/kg of body wt during 7 and 14 days. 2. Their brain, cerebellum, liver and kidney DNA, RNA and protein content were measured by conventional procedures. 3. The reference values of these rodents' cellular DNA were calculated through hepatocytes isolated following an intracardiac perfusion with collagenase in Hanks solution. 4. A concentration of 7.2 micrograms of DNA per 10(6) cells was found. 5. Phenytoin did not affect tissues of groups of animals receiving daily doses of 5 mg/kg of weight during 7 and 14 days of treatment; although a slight increase of protein concentration was observed in liver (P less than 0.01) and kidney (P less than 0.05). 6. RNA values were found to be significantly decreased in cerebellum (P less than 0.001), brain (P less than 0.05) and kidney (P less than 0.05) of those animals receiving the drug throughout 14 days. 7. DNA concentration was found to be decreased in all four tissues obtained from animals treated with daily doses of phenytoin of 100 (P less than 0.001) and 150 (P less than 0.001) mg/kg of body wt throughout 14 days. 8. These results indicate that phenytoin affected tissue cellularity only when administered at high doses and 14 days of interval of drug administration (P less than 0.001).
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PMID:Phenytoin effects on tissues of Mongolian gerbils (Meriones unguiculatus). 619 40

The collagenase activity in skin fibroblast cultures from three patients with rare forms of epidermolysis bullosa was assayed before and after proteolytic activation of the medium. Two of the patients had the recessive dystrophic form of the disease (REBD), which is generally associated with abnormal collagenase activity. The other patient had an atrophic mitis form of the disease (REBA), which has not previously been associated with defective collagen metabolism. However, a similar increase in collagenase activity was found in all three cases. The total collagen production of EB fibroblasts was also enhanced, being two to five times that of control cell lines, and the intracellular hydroxylases of collagen biosynthesis were higher in the case of two EB-cell lines. These changes reflect the compensatory increase in collagen synthesis which follows the increased degradation caused by excessive free collagenase activity. Diphenylhydantoin treatment of one REBD patient for 9 months improved her condition.
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PMID:Collagen metabolism in two rare forms of epidermolysis bullosa. 632 Aug 58

Junctional epidermolysis bullosa (EB) is a rare, heritable, blistering disease of the skin characterized by presence of bullae at birth, lack of scarring of the lesions, and early death. To date there has been no effective treatment for the disease. Phenytoin, which decreases collagenase activity in human skin explants and fibroblast cultures, has been used successfully to treat patients with recessive dystrophic EB. We found a marked decrease in new blister formation in one child with junctional EB during phenytoin therapy.
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PMID:Junctional epidermolysis bullosa. Treatment with phenytoin. 661 46

The mechanism by which phenytoin inhibits insulin release was studied. Insulin release and 45Ca2+ efflux were measured during perifusion of collagenase isolated rat islets after 2-day maintenance in tissue culture in the presence of a trace amount of 45Ca2+. Islets maintained in the absence of the isotope were used to measure 45Ca2+ uptake over 5 min. Glucose (16.7 mM) induced a biphasic release of insulin, which was accompanied by a biphasic increase in the rate of 45Ca2+ efflux above basal. Phenytoin (80 microM) added during second phase rapidly inhibited insulin release. In contrast, phenytoin added together with glucose failed to affect first phase, but reduced second phase release by 64%. Phenytoin failed to affect basal 45Ca2+ efflux in the presence or absence of Ca2+, nor did it interfere with the inhibitory effect of high glucose on Ca2+ efflux. The drug did not affect basal Ca2+ uptake, but significantly reduced glucose-induced Ca2+ uptake. Glucose utilization was not inhibited by phenytoin. It is suggested that phenytoin inhibits glucose-stimulated insulin release by interfering with Ca2+ uptake via voltage-dependent Ca2+ channels. The pattern of inhibition of insulin release appears to favor this conclusion as the second phase is more dependent on the stimulation of Ca2+ uptake than is the first phase.
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PMID:Phenytoin inhibition of insulin release. Studies on the involvement of Ca2+ fluxes in rat pancreatic islets. 675 43


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