Exocytosis couples to endocytosis of ferritin in parotid acinar cells from isoprenalin stimulated rats.
Distribution of acid phosphatase as a marker enzyme for lysosomes was investigated in the isoprenalin stimulated rat parotid gland. The enzyme was localized in lipofuscin-like bodies as well as in non-discharged granules. The appearance of these bodies was correlated in time to the appearance of smooth vesicles and reduction of the acinar lumen. Ferritin, used as a tracer and introduced into the stimulated gland via cannulated parotid ducts, was found in smooth vesicles, vacuoles and lipofuscin-like bodies throughout the cytoplasm of the acinar cells. Very often ferritin-containing vesicles were found in the vicinity of the Golgi complex. In most cases the vesicles containing ferritin also showed acid phosphatase reaction product. A possible correlation between the lysosomal system and the process of recycling and degradation of membranes in the stimulated gland is discussed.
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D003594:Cytoplasmic Granules / Q000502:physiology; D004705:Endocytosis; D005089:Exocytosis; D005293:Ferritins / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology*; D008062:Lipofuscin; D008247:Lysosomes / Q000201:enzymology / Q000502:physiology*; D008566:Membranes; D010306:Parotid Gland / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D013268:Stimulation, Chemical
D008062:Lipofuscin; D005293:Ferritins; D000135:Acid Phosphatase; D007545:Isoproterenol