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Microfilamentous system and secretion of enzyme in the exocrine pancreas. Effect of cytochalasin B

par Bauduin, Henri ;Stock, Christiane;Vincent, D.;Grenier, Jacques J.F.
Référence The Journal of cell biology, 66, 1, page (165-181)
Publication Publié, 1975

Article révisé par les pairs

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Résumé :

The microfilaments in the acinar cell of the exocrine pancreas are essentially located in the apical part of the cell: thin microfilaments (50 Å), cytochalasin B (CB) sensitive, form the axis of the microvilli and a network lying beneath the apical membrane; ticker filaments (100 Å), at least partly CB insensitive, form bundles parallel to the plasma cell membrane and the desmosomal links. CB interaction with the acinar cell of the exocrine pancreas involves at least two sites: a membrane site involved in the inhibitory effect of CB on the monosaccharide transport and a less sensitive site at the filamentous level at least partly responsible for the inhibitory effect of CB in the secretion of the exportable enzyme from the pancreatic cell. CB did not alter the energy balance of the acinar cell nor the exchanges of 45Ca between the extracellular medium and the pancreatic tissue. CB (2 x 10 -7 and 2 x 10 -6 M) has secretagogue properties whereas CB (2 x 10 -5 M) has inhibitory effect on stimulated secretion and secretagogue properties. The mechanism of these secretory effects is not yet explained. The analysis presented in this investigation affords strong evidence for the involvement of the microfilamentous network in the last steps of the secretory cycle in the acinar cell of the exocrine pancreas.