title: Studies on vinblastine-induced autophagocytosis in mouse liver. IV. Origin of membranes.
abstract: The origin of the limiting membranes of autophagic vacuoles (AV) in mouse hepatocytes was studied by cytochemical techniques. Autophagocytosis was induced by an intraperitoneal injection of vinblastine (50 mg/kg). The marker enzymes used were adenosine triphosphatase for the plasma membrane, glucose-6-phosphatase for the endoplasmic reticulum and thiamine pyrophosphatase for the Golgi apparatus and the endoplasmic reticulum. All the three enzymes showed a characteristic localization in both control and vinblastine-treated hepatocytes. The space between the limiting membranes of a few apparently newly formed AV's showed weak glucose-6-phosphatase activity. Neither adenosine triphosphatase nor thiamine pyrophosphatase activities were observed on or between the AV membranes. It was suggested that endoplasmic reticulum membranes may be used as a source of AV membranes in hepatocytes. The lack of glucose-6-phosphatase activity in the limiting membranes even of most of the newly formed AV's suggests a transformation process of the membranes destined to form AV, during which the enzyme activity characteristic for endoplasmic reticulum may disappear from them.
mesh_terms: D000251:Adenosine Triphosphatases / Q000032:analysis; D000818:Animals; D005952:Glucose-6-Phosphatase / Q000032:analysis; D008099:Liver / Q000201:enzymology / Q000648:ultrastructure*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010587:Phagocytosis / Q000187:drug effects*; D013834:Thiamine Pyrophosphatase / Q000032:analysis; D014747:Vinblastine / Q000494:pharmacology*
chemical_list: D014747:Vinblastine; D005952:Glucose-6-Phosphatase; D000251:Adenosine Triphosphatases; D013834:Thiamine Pyrophosphatase