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Updated: Jun 22, 2026

Assessing the Secretory Capacity of Pancreatic Acinar Cells
Published on: August 28, 2014
Transferrin secretory pathways in rat parotid acinar cells
Tomoko Nashida1, Sumio Yoshie, Akane Imai
1Department of Biochemistry, The Nippon Dental University, School of Life Dentistry at Niigata, Hamaura-cho, Niigata, Japan. nashida@ngt.ndu.ac.jp
Abstract:
Transferrin is the major iron transporter in blood plasma, and is also found, at lower concentrations, in saliva. We studied the synthesis and secretion of transferrin in rat parotid acinar cells in order to elucidate its secretory pathways. Two sources were identified for transferrin in parotid acinar cells: synthesis by the cells (endogenous), and absorption from blood plasma (exogenous). Transferrin from both sources is secreted from the apical side of parotid acinar cells. Endogenous transferrin is transported to secretory granules. It is secreted from mature secretory granules upon stimulation with a beta-adrenergic reagent and from smaller vesicles in the absence of stimulation. Exogenous transferrin is internalized from the basolateral side of parotid acinar cells, transported to the apical side by transcytosis, and secreted from the apical side. Secretory processes for exogenous transferrin include transport systems involving microfilaments and microtubules.
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