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)

More than 90 percent of the cells isolated from the mammary gland of lactating rats with 0.1 percent collagenase were viable by dye exclusion. Myoepithelial cells comprised about one-third of the mammary cells and appeared to be morphologically intact in electron micrographs. [(3)H]Oxytocin-binding activity was localized in an enriched myoepitheial cell fraction obtained by density gradient centrifugation of the isolated cells. The amount of [(3)H] oxytocin bound at 20 degree C and pH 7.6 was proportional to the concentration of oxytocin and the number of cells, reaching a steady state by 40 min. About 0.45 fmol of oxytocin were bound per 10(6) cells. There was a single class of independent binding sites with an apparent K(d), estimated from equilibrium conditions, of 5 nM. This value agrees within experimental error with the value calculated from the ratio of reverse to forward rate constants (5.8 x 10(-4)s(-1) and 2.2 x 10(5) M(-1)s(-1), respectively), consistent with a single-step model for the interaction of oxytocin with binding sites on the cells. Erythrocytes bound only 3.5 percent of the amount of oxytocin bound by an equal number of mammary cells. Oxytocin analogues competed with [(3)H]oxytocin for binding sites in the following order: [deamino]oxytocin > [4-threonine]oxytocin > oxytocin > [O- methyltyrosine]oxytocin > [8-lysine]vasopressin; [lysine]-bradykinin and [4-proline]oxytocin were not inhibitory in the dose ranges tested. These results demonstrate that isolated mammary cells possess oxytocin receptors with properties comparable to those found in broken mammary cell preparations.
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PMID:Binding of [3H]oxytocin to cells isolated from the mammary gland of the lactating rat. 19 65

The objective of this study was to isolate, purify, culture, and characterize myoepithelial cells from bovine mammary glands. Myoepithelial cells were separated from other mammary and blood cells after collagenase digestion and centrifugation using metrizoate-ficoll gradients. Myoepithelial cells were identified by their characteristic morphology and cloned using selective detachment. They contained many densely packed myofilaments, very few cytoplasmic organelles, elongated surface projections, and a dense, irregularly shaped nuclei. Some cells were as large as 1.2 mm in culture. Myoepithelial cells contained an extensive network of cytoskeletal proteins, including alpha-smooth muscle actin, alpha-actinin, and vimentin. When cultured, they tended to repel one another and never grew as closely associated cells. The myoepithelial nature of these cells was verified by showing that they contracted in response to oxytocin, bound oxytocin, and did not produce casein. Myoepithelial cells from fetal and lactating glands grew very well in culture. Active division of myoepithelial cells could be maintained for at least 3 mo, and cells could be serially subcultured at least seven times. The successful isolation and culture of bovine mammary myoepithelial cells make utilization of these cells possible in order to study their role in mammary growth and differentiation and milk ejection.
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PMID:Bovine mammary myoepithelial cells. 1. Isolation, culture, and characterization. 147 4

The objective of this study was to examine interactions of bovine myoepithelial and epithelial cells in vitro. Mammary tissue was dissociated with collagenase into myoepithelial and epithelial cells. Myoepithelial and epithelial cells were separated by differential centrifugation. Both cell types were cultured on plastic in RPMI-1640 and Iscove's Modified Dulbecco's Modified Eagle Medium supplemented with 10% horse serum and 5% fetal bovine serum. Our data revealed that conditioned medium from epithelial cells caused a small but significant reduction in proliferation of myoepithelial cells from fetal mammary glands. Myoepithelial-epithelial cell interaction in culture was characterized by myoepithelial cells with extended filopodia that could grow on top of confluent monolayers of epithelial cells, imitating the in vivo situation. In confluent monolayers of epithelial and myoepithelial cells in coculture, small domelike structures consisting of mixtures of epithelial and myoepithelial cells were observed. These structures greatly resembled the in vivo organization of the bovine mammary gland. Furthermore, myoepithelial cells were capable of migration toward individual colonies of epithelial cells or single epithelial cells. Myoepithelial cells organized epithelial cells into well-defined colonies. Myoepithelial cells may play an important role in organizing the architectural framework of the mammary gland during growth and development.
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PMID:Bovine mammary myoepithelial cells. 2. Interactions with epithelial cells in vitro. 147 5

Myoepithelial and secretory cells from the mammary gland of the lactating rat have been isolated, purified, and characterized. Mammary tissue was dissociated with collagenase into basket-like networks of myoepithelial cells and single secretory cells. Because of their larger size, the myoepithelial cell networks could be separated from other mammary and blood cells by differential centrifugation. Isolated secretory cells were purified by isopycnic centrifugation in 25% bovine serum albumin. The purified myoepithelial and secretory cells were viable, as shown by the incorporation of 32P into distinct macromolecules that were separable by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both myoepithelial and secretory cells retained their characteristic morphology after isolation and purification, as shown by light, transmission, and scanning electron microscopies. The isolated myoepithelial cells were unique and, thus, distinguishable from other mammary cells in a number of respects; they 1) contracted in response to the addition of oxytocin, 2) bound [3H]oxytocin specifically, 3) accounted for the content of alkaline phosphatase and [Na+ + K+]ATPase in mammary tissue, and 4) reacted specifically with antiserum prepared against purified myoepithelial cells. The purified secretory cells were unique in possessing glucose-6-phosphate dehydrogenase activity. The different cell markers not only gave independent estimates of the purity of the cell fractions, but they also may be helpful in identifying mammary cells in stages of differentiation and neoplastic transformation.
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PMID:Purification and characterization of mammary myoepithelial and secretory cells from the lactating rat. 624 56

Biochemical and morphological properties of the Harderian gland of the mouse were examined by combining autoradiographic, biochemical, and electron microscopic techniques. Autoradiographs show that the radioactive carbon from [U-14C]glucose injected to the abdominal cavity is completely incorporated into the acid-insoluble substances within 30 minutes. The results of chemical analysis show that the main components of this gland are glyceryl ether diesters and phospholipids. Scanning electron microscopy shows numerous lipid droplets in the secretory cells and alveolar lumina. Myoepithelial cells lie between the secretory cell base and the basement membrane and have a basket-like distribution of processes as confirmed by hydrochloric acid and collagenase digestions. Myofilaments are demonstrated in the cytoplasm. Two types of secretory cells (A and B) comprise the alveolar epithelium and can be differentiated under the electron microscope. The cytoplasm of both contains numerous vacuoles. The vacuoles are almost empty in A cells, which are more numerous constituent of the alveolar epithelium than B cells. However, the vacuoles of the B cells contain densely osmiophilic material. In both, cell types show a merocrine mode of secretion. Unmyelinated nerve cell endings occur in the interstices of the connective tissue, and contain clear or cored vesicles.
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PMID:An autoradiographic, biochemical, and morphological study of the harderian gland of the mouse. 699 6

The response of mammary myoepithelial cells to oxytocin was studied by monitoring the level of phosphorylation of the 20,000 mol wt light chain of myosin. Myoepithelial cells were obtained by collagenase dispersion of involuted rat mammary tissue. The cells were equilibrated with [32P]orthophosphate, and then stimulated with oxytocin. Phosphorylated proteins were separated by polyacrylamide gel electrophoresis, and incorporation of 32P into the proteins was detected by autoradiography. Nanomolar concentrations of oxytocin caused a 3-fold increase in the level of phosphorylation of the myosin light chain within 0.5 min. When the cells were incubated with oxytocin in a calcium-free medium, there was only a transient phosphorylation of myosin. However, readdition of calcium to these cells resulted in phosphorylation of the myosin light chain. The results suggest that calcium is involved in the intracellular events following stimulation of the cells with oxytocin.
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PMID:Phosphorylation of myosin in mammary myoepithelial cells in response to oxytocin. 707 45