title: First observations on enzymatic activity and protein content of vesicles separated from rat epididymal fluid.
abstract: Fluid of rat cauda epididymidis was obtained by flushing the duct with 0.25 mol l-1 sucrose in 0.01 mol l-1 Tris-HCl buffer pH 7.4. The fluid was centrifuged at 600 x g for 15 min and the sperm free supernatant was centrifuged at 47,000 x g for 1 h. The sediments observed with the electron microscope consisted of a heterogeneous population of membrane-bound vesicles similar to those seen in the intact organ. In the sediment containing the vesicles the activity of beta-galactosidase was mostly unavailable for the substrate showing a high degree of latency: the activity became soluble after a treatment with 0.5% saponin. The activity of N-acetyl-galactosaminadase instead, was mainly available for the substrate and soluble in buffer containing 0.6 mol l-1 KCl. It was then inferred that beta-galactosidase is located inside vesicles with no or little affinity for the membrane, while N-acetylglucosaminadase is bound to the external surface of vesicles. Supernatants and precipitates from suspensions of vesicles in buffered 0.5% saponin were analysed for proteins by gel electrophoresis. The electrophoretic patterns of the sediments were very different from those of supernatants and showed a number of bands greater than that of the latter. The vesicles are believed to arise from the epididymal epithelium, but their physiological role is unknown.
authors.affiliation: Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.
authors.forename: M W
authors.initials: MW
authors.lastname: Fornés
authors.forename: A
authors.initials: A
authors.lastname: Barbieri
authors.forename: M A
authors.initials: MA
authors.lastname: Sosa
authors.forename: F
authors.initials: F
authors.lastname: Bertini
mesh_terms: D000818:Animals; D001826:Body Fluids / Q000201:enzymology / Q000378:metabolism; D004822:Epididymis / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D014617:Vacuoles / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D011506:Proteins; D001616:beta-Galactosidase