title: [Isolation and characteristics of the plasma membrane fraction from the swine myometrium].
abstract: An accelerated method is developed for isolating a fraction of plasma membranes of pig myometrium using ultracentrifugation within the sucrose density gradient (15% and 30%). The membranes possessed the high activity of 5'-nucleotidase and Na+, K+-ATPase and the low activity of rhotenon-insensitive NADH-cytochrome c reductase. The vesicularized preparations of plasma membranes are able of ATP-dependent accumulation of Ca2+ (7.5 +/- 0.3 nmol. 45Ca2+ per 1 mg of protein for 15 min). Phosphate increases the calcium accumulation in the presence of ATP and Mg2+. Ionophore A 23187 promotes a complete and rapid release of the previously active-accumulated calcium. The release of 45Ca2+ accumulated by the membrane fraction may be reached by introduction of 1 mM EGTA or DS-Na into the incubation medium, that evidences for the cation accumulation inside closed structures. Using concanavalin-A-sepharose 4B it is shown that 60% of membrane vesicles are turned inside out. The low saponine concentrations (0.0005%) which inhibit Ca2+-accumulation by plasma membranes but not by the endoplasmic reticulum inhibit this process by 60-70% in preparations of the isolated membrane fraction. The method has certain advantages over the previously applied methods used for isolating of plasma membrane fragments from smooth muscles.
mesh_terms: D000251:Adenosine Triphosphatases / Q000032:analysis; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002458:Cell Fractionation; D002462:Cell Membrane / Q000032:analysis* / Q000201:enzymology; D005260:Female; D008722:Methods; D009215:Myometrium / Q000032:analysis* / Q000201:enzymology; D011943:Receptors, Adrenergic, beta / Q000032:analysis; D013552:Swine
chemical_list: D011943:Receptors, Adrenergic, beta; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D002118:Calcium
vernacular_title: Vydelenie i kharakteristika fraktsii plazmaticheskikh membran miometriia svin'i.