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)

Leupeptin, antipain, tosyl-lysylchloromethane (Tos-Lys-CH2Cl) and benzyloxy-carbonylphenylalanylalanyldiazomethane (Z-Phe-Ala-CHN2) inhibit reversibly the resorption induced by parathyroid hormone or heparin in cultured mouse bones. Leupeptin and antipain do not affect collagenase production and activity or the enhanced secretion of beta-glucuronidase induced by the bone-resorbing agents. They might thus act by a direct (extracellular?) inhibition of lysosomal thiol proteinases.
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PMID:Inhibition of bone resorption in culture by inhibitors of thiol proteinases. 627 2

Isolated cells obtained from foetal rat bone (calvarium) by collagenase digestion can be separated into three subpopulations on the basis of surface charge by free flow electrophoresis. These subpopulations have been tentatively identified by numerical, biochemical and functional criteria and are believed to be composed of: (1) bone resorbing cell types, designated Peak I cells; (2) fibroblasts and loose connective tissue cells, designated Peak II cells; and (3) a mixture of osteoblasts and osteoprogenitor cell types, designated Peak III cells. The anatomical position of these subpopulations in the whole calvarium was determined by comparing the results of histochemical and morphological experiments with the results of biochemical experiments. It was found that Peak I cells are located predominantly on the ventral (endocranial) surface, Peak II cells in the connective tissue periosteal membranes and Peak III cells on the dorsal (ectocranial) surface and in the suture line areas. The response of these cell types to parathyroid hormone and calcitonin with regard to c amp production and 45Ca release from devitalized bone is examined and indicates that cells from Peak I and Peak III both respond to parathyroid hormone but only the cells from Peak I respond to calcitonin.
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PMID:Electrophoretically separated bone cell types from the foetal rat calvarium: a histochemical and biochemical study. 628 25

Medullary and cortical tubular cells were prepared from rat kidneys with collagenase treatment. Arginine vasopressin (AVP) stimulated cyclic AMP production both in medullary and cortical cells with a dose-response relationship at concentrations ranging from 10 microU/ml to 10 mU/ml, whereas parathyroid hormone (PTH) and calcitonin did only in the latter. Using this medullary cell system, effects of acute changes in endogenous plasma AVP levels in vivo on its cyclic AMP responsiveness to AVP (10 mU/ml) in vitro were examined. Acute elevation of plasma AVP levels induced by ip injection of 20% (w/v) polyethylene glycol-isotonic saline solution 3 h prior to sacrifice resulted in a 33% decrease in cyclic AMP responsiveness to AVP (desensitization). More prolonged elevation of plasma AVP levels by water restriction for 48 h, on the other hand, increased the responsiveness by 38 to 81%, which was restored to basal levels by ad libitum intake of water for another 48 h (positive feedback regulation). These maneuvers did not alter the cyclic AMP responsiveness to PTH (10 micrograms/ml) in cortical cells. The results suggest that AVP-stimulated adenyl cyclase in rat renal medulla may be regulated by changes in endogenous AVP levels even within the physiological range.
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PMID:Altered cyclic AMP responsiveness to vasopressin in rat renal medullary dispersed cells by acute elevation of endogenous vasopressin. 629 51

The enzymatic activity of bone matrix vesicles from parathyroidectomized rats was determined and compared to the activity of vesicles from sham operated and normal animals. The vesicles were isolated from the alveolar bone by collagenase digestion and differential centrifugation and further purified on a discontinuous sucrose density gradient. The amount of extractable protein and the activity of alkaline phosphatase, acid phosphatase, and ATPase in the vesicle fractions thus obtained did not differ significantly from the values characteristic of preparations from control rats. It may therefore be suggested that parathyroid hormone depletion and the associated hypocalcemia have no significant effect on the occurrence and phosphatase activity of bone matrix vesicles.
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PMID:Extracellular matrix vesicles in rat bone after parathyroidectomy. 629 69

The effect of aluminum on parathyroid hormone secretion was examined using collagenase-dispersed bovine parathyroid cells. An increase in the medium aluminum concentration over the range of 0.5 to 2.0 mM, in low calcium medium, progressively inhibited the secretion of radioimmuno-assayable hormone. At 2.0 mM aluminum hormone secretion was inhibited by 68% while high medium calcium, without aluminum, maximally inhibited parathyroid hormone secretion only 39%. Individually, 2.0 mM aluminum or 2.0 mM calcium inhibited isoproterenol-stimulated hormone secretion by 43%. Either metal suppressed basal and isoproterenol-stimulated cyclic AMP levels of the parathyroid cells. That the inhibitory effect of aluminum on parathyroid hormone secretion was not due to an irreversible toxic effect was demonstrated by a restoration of normal secretion when cells were returned to 0.5 mM calcium medium without aluminum. The incorporation of [3H]leucine into total cell protein, parathyroid secretory protein, proparathyroid hormone, or parathyroid hormone was not affected by aluminum. The secretion of radiolabeled protein was, however, inhibited by aluminum. These results suggest that aluminum does not affect protein biosynthesis of the parathyroid cell or the conversion of proparathyroid hormone to parathyroid hormone. Aluminum appears to directly affect the secretion of protein from dispersed parathyroid cells.
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PMID:Suppression of parathyroid hormone secretion by aluminum. 630 27

Bone cells released from perinatal rat calvaria by digestion with clostridial peptidase were separated into two distinct populations (designated types B and C) by equilibrium density centrifugation on a two-step gradient of Percoll. They were extensively characterized by light and electron microscopy and for behaviour in culture, acid and alkaline phosphatase activity, collagen synthesis, collagenase secretion and adenylate cyclase response to parathyroid hormone (PTH) and calcitonin. Type C cells were predominantly large with up to seven nuclei and an unusual cytoplasmic appearance in cytocentrifuge preparations. They did not proliferate in culture and we have established culture conditions which prevented their overgrowth by contaminating proliferative cells. In culture these cells had low alkaline and high acid phosphatase and high aryl sulphatase activity, and synthesized little collagen. In contrast type B cells were mostly smaller and many had irregular cytoplasmic projections. In culture they became polygonal in shape, proliferated rapidly, and reached confluence in 4-5 days. These were low in aryl sulphatase and acid phosphatase, high in alkaline phosphatase activity, and synthesized labelled collagen actively with [3H]proline and ascorbic acid included in the culture medium. The two cell population were found to differ in culture in two important further respects. First, the type C cells showed an adenylate cyclase response to calcitonin but not to PTH, while the converse was true for type B cells; this was so over at least a 20-fold range of isobutylmethyl xanthine concentration. Secondly, type C cells in culture secreted an active collagenolytic enzyme. Type B cells secreted much lower levels of a predominantly latent collagenase which required activation by mersalyl. Co-culture of type C and type B cells led to a marked reduction in the content of active collagenase in the culture medium.
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PMID:Separation of two bone cell populations from fetal rat calvaria and a study of their responses to parathyroid hormone and calcitonin. 631 50

During bone remodeling, activation of resorption is followed by a cycle of formation and this ordered sequence of events has long suggested that local interactions between osteoclasts and osteoblasts are an important regulatory mechanism in bone metabolism. To study this phenomenon, we have prepared bone cells containing primarily osteoclasts by brief digestion of mice calvariae in collagenase, overnight attachment to polystyrene tissue culture flasks in serumless medium supplemented with OB (osteoblast) cell conditioned medium and subsequent growth in low serum. These OC (osteoclast) cells were found to be highly enriched in acid phosphatase activity and expressed cAMP responses to PTH (parathyroid hormone) and prostaglandin E2 but exhibited no PTH-stimulated hyaluronate synthesis in contrast to prostaglandin E2. PTH effects on hyaluronate, however, could be restored upon coculture of OC cells with OB cells (noncontact) or with OB cell conditioned medium, thereby suggesting that OB cells regulate OC cell PTH responsiveness and/or differentiation by soluble cell products secreted into the medium.
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PMID:Paracrine interactions in bone-secreted products of osteoblasts permit osteoclasts to respond to parathyroid hormone. 632 52

Prostaglandin E2 (PGE2) over the concentration range 10(-5)-10(-7) M stimulated calcium uptake in osteoclastic-enriched populations isolated by sequential collagenase digestions of newborn rat calvaria. This effect was on initial calcium uptake occurring at 5 min at 37 degrees C but was not present when isotopic equilibrium was approached (60 min). Prostacyclin (PGI2, PGE1 and PGF2 alpha) stimulated osteoclastic calcium uptake in a similar manner, but with slightly smaller effects than PGE2. Under identical conditions, significant effects of PG were not observed in osteoblastic cells isolated from the same bones by extended collagenase digestions. Combined treatment with PGE2 and parathyroid hormone (PTH) at concentrations which produced no individual effects resulted in a significant increase in calcium uptake in osteoclastic cells. During a 48-h culture period, osteoblastic populations released significantly greater amounts of PGE2 than osteoclastic populations. Pre-incubation for 1 h at 37 degrees C with the prostaglandin cyclo-oxygenase antagonists, indomethacin and flufenamic acid, had no effect on calcium uptake in osteoclastic cells, but resulted in significant decreases in osteoblastic cells. The PGE2-induced increase in calcium uptake on osteoclastic cells was not altered by indomethacin or flufenamic-acid pretreatment. However, after treatment with these inhibitors, a significant response to PGE2 was observed in osteoblastic cells.
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PMID:Effects of prostaglandins on rat calvarial bone-cell calcium. 639 25

The metabolism of labeled glucose by collagenase-dispersed bovine parathyroid cells was examined. When the medium calcium ion concentration was increased to 2.0 mM, the rate of 14CO2 release from [1-14C]glucose was increased 169 +/- 45% compared with the rate of 0.5 mM calcium. There was no significant change in the rate of 14CO2 release from [6-14C]glucose by this maneuver. The greatest increase in 14CO2 release and decrease in parathyroid hormone secretion occurred between medium calcium ion concentrations of 0.5-1.5 mM. This difference in the metabolism of glucose represents a true increase in hexose shunt activity because the incorporation of label from either [1-14C]- or [6-14C]glucose into parathyroid tissue lipids was equal. This suggests equilibration of label at the level of triose-phosphates. The increase in hexose shunt activity was not due to a calcium-mediated increase in glucose uptake because calcium changes did not affect 2-[3H]deoxyglucose transport by the cells. Phenazine methosulfate added to cells incubated at 0.5 mM calcium selectively increased hexose shunt activity in a dose-dependent manner (91 +/- 33% overall) and concomitantly inhibited parathyroid hormone secretion 65% overall at 0.5 mM calcium. The compound 6-aminonicotinamide inhibited hexose shunt activity but could not overcome the inhibition of hormone secretion at 2.0 mM calcium. A decrease in protein biosynthesis cannot fully explain the inhibition of hormone secretion by calcium or phenazine methosulfate because [3H]-leucine incorporation into total cell protein was not as affected as secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of hexose monophosphate shunt in parathyroid hormone secretion. 641 80

Deflazacort is a new synthetic glucocorticoid which is an oxazoline derivative of prednisolone. In previous studies, it was shown that deflazacort, depending on the test model used, not only showed considerably more antiinflammatory potency than prednisolone in animals but also caused less deleterious effects on bone mineral metabolism than equivalent amounts of other glucocorticoids in man. In this study, we have compared the effects of deflazacort with those of dexamethasone on the synthesis of collagen in various rat bone cell populations and chondrocytes. Three bone cell populations were prepared by sequential time-dependent collagenase treatment of 1-day-old rat calvaria. Each cell population was further purified on a Percoll gradient (10-90%) yielding three populations of which two are different in alkaline and acid phosphatase and response to parathyroid hormone. A 3-day treatment of bone cell populations with deflazacort and dexamethasone (10(-11)-10(-5) M) revealed that both glucocorticoids, although at different concentrations, inhibited collagen synthesis. 21-desacetyl-deflazacort (5 beta, 11 beta, 16 beta)-11,21-dihydroxy-2'-methyl-5-H-pregna-1-enol [17,16-d]oxazole-3,20-dione), the presumably active form of the steroid, which is formed in vivo after administration, produced nearly identical results as its precursor. Glucocorticoid concentrations at which inhibition was initially observed were 10(-9) M and 10(-7) M for dexamethasone and deflazacort respectively. Inhibition of collagen synthesis was significantly impaired only in cells isolated from bone during early tissue digestion, and not in those obtained during extensive collagenase treatment. Chondrocytes isolated from articular cartilage of 3-month-old rabbits and grown in primary cultures did not respond to either steroid.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparative study of deflazacort, a new synthetic corticosteroid, and dexamethasone on the synthesis of collagen in different rat bone cell populations and rabbit articular chondrocytes. 643 Apr 98


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