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)

Methods for isolating chondrocytes from the craniofacial complex and culturing them in vitro were established. Chondrocytes which were isolated by collagenase digestion from mandibular condylar cartilage, nasal septal cartilage, and spheno-occipital synchondrosis grew well in vitro. All three types of chondrocytes actively synthesized glycosaminoglycans, a differentiated phenotype of chondrocytes, and responded well to parathyroid hormone. However, some different characteristics were noted among the three types of chondrocytes in culture.
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PMID:Studies on chondrocytes from mandibular condylar cartilage, nasal septal cartilage, and spheno-occipital synchondrosis in culture. I. Morphology, growth, glycosaminoglycan synthesis, and responsiveness to bovine parathyroid hormone (1-34). 658 75

Previous studies of lead metabolism in bone organ culture have defined, in part, an exchangeable bone lead compartment regulated by the same ions and hormones that normally control bone cell metabolism. This study was undertaken to further characterize this subcompartment of exchangeable lead and to examine possible interactions between lead and calcium in isolated bone cell populations. Bone cells, derived from mouse calvaria, were enriched for osteoclasts (OC) and osteoblasts (OB) by a sequential collagenase digestion. We found that (1) the uptake of 210Pb by OC cells was rapid, and OC cells had greater avidity for lead, compared to OB cells, at concurrent time points of incubation, (2) OB cells showed very little increase in lead uptake as medium lead concentrations were increased from 6.5 to 65 microM, in contrast, the uptake of lead by OC cells was almost linear, (3) after loading OC cells with 210Pb, significant release of label (approximately 15 to 30%) occurred within short time periods (less than or equal to 2 hr) during incubations in chase medium, (4) parathyroid hormone (PTH) at physiological concentrations effected a marked increase in 210Pb and 45Ca uptake in OC cells, after 5 min of incubation, Pb accumulation into OC cells continued as calcium uptake markedly decreased, (5) this PTH effect on 210Pb uptake was linear over PTH concentrations of 50 to 250 ng/ml, and (6) rising medium concentrations of lead (greater than or equal to 26 microM) markedly enhanced/exaggerated calcium uptake by OC cells, far above that produced by physiological concentrations of PTH. These data indicate that (1) quantitatively, OC cells are the predominant cell type in the metabolism of lead in this in vitro system of OC and OB cell monolayers, (2) mediated incorporation of lead into OC cells occurs and likely involves changes in membrane permeability effected by hormonal stimuli, such as PTH, and (3) modulations in cellular calcium metabolism induced by lead at low concentration may have the potential of disturbing multiple cell functions of different tissues that depend upon calcium as a second messenger.
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PMID:The metabolism of lead in isolated bone cell populations: interactions between lead and calcium. 663 77

Renal cells from Vitamin D-deficient and 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]-repleted chicks were isolated by a collagenase-hyaluronidase procedure. Exclusion of trypan blue and respiratory measurements indicate that the cells were functionally intact and metabolically active. The uptakes of phosphate and alpha-methylglucoside were stimulated markedly by Na+ in the extracellular medium. Phosphate uptake in the presence of Na+ was saturable with respect to phosphate concentration; half-maximal activity was obtained with approximately 0.2 mM. Three hours after 1,25-(OH)2D3 was injected into vitamin D-deficient chicks the Na+-dependent phosphate uptake by the isolated cells had increased about 40%, i.e., 2.00 compared with 1.44 nmol.min-1.mg protein-1. Phosphate uptake in the presence of K+ in the extracellular medium and alpha-methylglucoside uptake in the presence or absence of Na+ were unchanged. In a secondary response found 17 h after 1,25-(OH)2D3 injection, Na+-dependent phosphate uptake decreased. Serum concentrations of phosphorus and calcium were not measurably changed in the 3-h repleted bird, but both levels were increased 17 h after treatment. Administration of phosphate into vitamin D-deficient chicks, so that the serum concentration of phosphorus was raised to that of the 17-h 1,25-(OH)2D3 repleted animal, effected a comparable decrease in phosphate uptake. Serum calcium levels were not altered by this treatment. The actions of parathyroid hormone in stimulating adenylate cyclase and in inhibiting phosphate uptake were notably blunted in the vitamin D-deficient chick. Sensitivity to parathyroid hormone was not restored until several days after 1,25-(OH)2D3 repletion. These findings suggest that the initial response to 1,25-(OH)2D3, to increase renal phosphate uptake, and the secondary response, to decrease phosphate uptake, were by parathyroid hormone-independent processes. The results also indicate that the isolated renal cell represents an excellent model for studying the mechanism by which 1,25-(OH)2D3 regulates phosphate transport in the kidney.
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PMID:Effects of 1,25-(OH)2D3 administered in vivo on phosphate uptake by isolated chick renal cells. 689 66

Parathyroid hormone decreased the incorporation of [3H]proline into collagenase-digestible protein in cultured 21-day fetal rat calvaria but had little effect on the labeling of noncollagen protein. After 24 hr of culture, there was a 50% reduction in collaghen synthesis and a 40% decrease in the level of functional procollagen mRNA as measured in a reticulocyte lystate translation assay. The effect of parathyroid hormone on both parameters was detectable after 6 hr of treatment. In these cultures, there was also a substantial degradation or release of newly synthesized collagen from the calvaria, but parathyroid hormone had little effect on the release of collagen into the medium. These results suggest that parathyroid hormone inhibits collagen synthesis primarily by decreasing the steady-state level of procollagen mRNA.
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PMID:Parathyroid hormone alters collagen synthesis and procollagen mRNA levels in fetal rat calvaria. 693 1

Certain metabolic properties of hormonally responsive osteogenic sarcoma cells derived from a transplantable rat tumor have been compared with those of related normal rat bone cells. All studies were carried out on cells grown in monolayer culture. Normal rat bone cells derived by repeated collagenase/trypsin digestion of newborn rat calvaria. Bone cells selected for comparison were thought to be osteoblast-like, as judged by enrichment of alkaline phosphatase and adenylate cyclase responsiveness to parathyroid hormone and prostaglandin E2. The adenylate cyclases of the two cell strains were similarly stimulated by a range of prostanoids and their metabolites and analogs. Morphology showed the two cell strains to be similar; the only obvious difference was a multilayering of cells in the sarcoma cultures, while the normal cultures showed abundant extracellular fibril formation which was not seen in the tumor cells. Investigation of the cAMP-dependent protein kinase isoenzymes showed the presence of two forms in both cell types, one eluting at a low salt concentration and the other at a high salt concentration. There was approximately twice the amount of the first isoenzyme compared to the second isoenzyme. The results indicate the usefulness of the two cell strains to elucidate further the molecular mechanisms of action of parathyroid hormone and prostaglandins.
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PMID:Functional properties of hormonally responsive cultured normal and malignant rat osteoblastic cells. 693 60

The effects of lithium on calcium-regulated parathyroid hormone (PTH) release were assessed in collagenase-dispersed bovine parathyroid cells. Preincubation for 4 hours with LiCl caused a dose-dependent increase in the concentration of calcium required for half-maximal inhibition of immunoreactive PTH release (the "set-point" for calcium). A significant increase in "set-point" was observed following exposure to 1.25 mM lithium, a concentration within the therapeutic range for man. This effect required preincubation with LiCl, was not seen with NaCl or KCl, and persisted despite removal of extracellular lithium. This lithium-induced abnormality in calcium-regulated PTH secretion may be a useful model system for analyzing the analogous defect in secretory control in primary hyperparathyroidism.
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PMID:Lithium induces abnormal calcium-regulated PTH release in dispersed bovine parathyroid cells. 722 89

The effects of calcitonin, vasoactive intestinal peptide (VIP), parathyroid hormone (PTH) and isoprenaline on intracellular cAMP accumulation were determined in the distal tubule (DCT) microdissected from collagenase-treated rabbit kidney. In DCTb (the initial "bright" portion) calcitonin (10 ng/ml) elicited a highly reproducible response 203.7 +/- 19.1 fmol cAMP mm-1 4 min-1 (SE,N = 13) whereas VIP-induced cAMP accumulation was less and more variable from one experiment to another (1 microM, 97.2 +/- 17.8 fmol mm-1 4 min-1, SE, N = 12). When used in combination, these two agonists were non-additive, indicating stimulation of a single pool of cAMP in DCTb. In DCTg, ("granular") which consists of at least two cell types, PTH (100 nM) elicited a marked, reproducible accumulation of cAMP (154.3 +/- 27.0 fmol mm-1 4 min-1; SE, N = 5). Isoprenaline (1 microM) and VIP (1 microM) induced much smaller increases in cAMP levels 20.9 +/- 2.7 and 29.4 +/- 4.1 fmol mm-1 4 min-1 (SE, N = 5) respectively, and, when used in combination, were non-additive, demonstrating that VIP and isoprenaline are active on the same cell type. In DCTb, prostaglandin E2 (PGE2) inhibited both calcitonin- and VIP-stimulated cAMP accumulation (calcitonin 57.8 +/- 2.7% inhibition, SE, N = 16; VIP, 80.6 +/- 2.1% inhibition, SE, N = 5). The EC50 values for calcitonin were 1.21 +/- 0.33 ng/ml and 1.83 +/- 0.25 ng/ml (SD, N = 3) in the absence and presence of PGE2 (300 nM) respectively with an IC50 for PGE2 of 26.3 +/- 6.3 nM (SE, N = 4).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of prostaglandin E2 on agonist-stimulated cAMP accumulation in the distal convoluted tubule isolated from the rabbit kidney. 768 23

We have compared the effects of a general matrix metalloproteinase (MMP) inhibitor (CT435) with those of a concentration-dependent specific gelatinase inhibitor (CT543; Ki < 20 nM) on bone resorption in vitro. The test systems consisted of measuring: (i) the release of 45Ca2+ from prelabelled mouse calvarial explants; (ii) the release of 45Ca2+ from prelabelled osteoid-free calvarial explants co-cultured with purified chicken osteoclasts; and (iii) lacunar resorption by isolated rat osteoclasts cultured on ivory slices. Both CT435 and CT543 dose-dependently inhibited the release of 45Ca2+ from neonatal calvarial bones stimulated by either parathyroid hormone or 1,25-dihydroxyvitamin D3. Moreover, CT543 produced a 40% inhibition at a concentration (10(-8) M) selective for the inhibition of human gelatinases A and B. CT435 (10(-5) M) and CT543 (10(-5) M) partially inhibited the release of 45Ca2+ from osteoid-free calvarial explants by chicken osteoclasts with a maximum of approximately 25% for unstimulated cultures, and approximately 36% for cultures stimulated by interleukin-1 alpha (IL-1 alpha; 10(-10) M). Neither inhibitor prevented lacunar resorption on ivory by unstimulated rat osteoclasts, but the compounds produced a partial reduction in both the number and total surface area of lacunae in IL-1 alpha-stimulated cultures, with maximal action at 10(-5) M. Neither of the inhibitors affected protein or DNA synthesis, nor the IL-1 alpha-stimulated secretion of the lysosomal enzyme beta-glucuronidase. Immunocytochemistry demonstrated that isolated rabbit osteoclasts constitutively expressed gelatinase A and synthesized gelatinase B, collagenase and stromelysin, as well as the tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) following IL-1 alpha stimulation. These experiments have shown that in addition to collagenase, gelatinases A and B are likely to play a significant role in bone resorption. They further suggest that MMPs produced by osteoclasts are released into the sub-osteoclastic resorption zone where they participate in bone collagen degradation.
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PMID:The effects of selective inhibitors of matrix metalloproteinases (MMPs) on bone resorption and the identification of MMPs and TIMP-1 in isolated osteoclasts. 769 5

We have previously shown that the rat osteoblastic cell line UMR 106-01 responds to parathyroid hormone treatment by secreting interstitial collagenase. Secreted collagenase reaches a maximal concentration 12-24 h after parathyroid hormone stimulation, but then declines to undetectable levels by 96 h. Neither spontaneous nor cell-mediated extracellular degradation could account for this disappearance, since the enzyme maintained stability in both fresh and conditioned media. Instead, a cell-mediated binding mechanism was suggested by the rapid and saturable removal of exogenous purified rat collagenase at 37 degrees C. Binding studies using 125I-collagenase at 4 degrees C indicated a saturable receptor of a single class and 12,000 receptors per cell (Kd = 5 x 10(-9) M). A time course revealed specific receptor-mediated binding within 10 min and equilibrium by 60 min, while dissociation experiments further demonstrated reversibility. The kinetics of 125I-collagenase binding are characterized by the association (k1 = 4 x 10(6) M-1 min-1) and dissociation (k-1 = 2 x 10(-3) min-1) rate constants. The receptor was shown to be specific for rat collagenase since a host of related and unrelated proteins failed to compete for binding. Internalization studies revealed maximal intracellular accumulation at 30 min and complete degradation by 90 min, suggesting this receptor functions in these osteoblastic cells to eliminate extracellular collagenase.
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PMID:Identification of a specific receptor for interstitial collagenase on osteoblastic cells. 792 84

Parathyroid hormone-related peptide (PTHrP) has been shown to be the pathogenic agent in humoral hypercalcemia of malignancy (HHM), but the molecular forms that are secreted have not been fully characterized. PTHrP 1-34 has effects similar to parathyroid hormone (PTH), but C-terminal regions of the peptide, such as the 107-139 fragment found to inhibit resorption in a study by Fenton et al (1991), may have other biological activities not shared with PTH. We have compared the effects of the longer forms of recombinant human PTHrP (hPTHrP 1-84, 1-108, and 1-141) with hPTHrP 1-34 and synthetic bovine PTH (bPTH) 1-34 on bone resorption and formation in cultured neonatal mouse calvariae and fetal rat long bones. hPTHrP 1-84, 1-108, and 1-141 were qualitatively similar to hPTHrP 1-34 and PTH 1-34 in stimulating 45Ca release from both neonatal mouse calvariae and fetal rat long bones and in inhibiting the incorporation of [3H]-proline into collagenase digestible protein (CDP) and stimulating the incorporation of [3H]-thymidine (3H-TdR) in neonatal mouse calvariae. However, hPTHrP 1-108 and 1-141 were less potent at stimulating 45Ca release and inhibiting CDP labeling than hPTHrP 1-34, while hPTHrP 1-84 showed an intermediate potency. Since hPTHrP 1-108 and 1-141 were quite similar in potency, the difference cannot be attributed to an inhibitory effect of the 107-139 fragment. All the peptide lengths tested showed similar potency in stimulating [3H]-TdR incorporation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of the effects of various lengths of synthetic human parathyroid hormone-related peptide (hPTHrP) of malignancy on bone resorption and formation in organ culture. 826 45


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