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Insulin, not C-peptide (proinsulin), is present in crinophagic bodies of the pancreatic B-cell

Ravazzola, M.
Amherdt, M.
Yanaihara, C.
Yanaihara, N.
Renold, A. E.
Published in The journal of cell biology. 1984, vol. 98, no. 1, p. 222-228
Abstract We have obtained evidence by autoradiography and immunocytochemistry that mature secretory granules of the pancreatic B-cell gain access to a lysosomal compartment (multigranular or crinophagic bodies) where the secretory granule content is degraded. Whereas the mature secretory granule content shows both insulin and C-peptide (proinsulin) immunoreactivities, in crinophagic bodies only insulin, but not C-peptide, immunoreactivity was detectable. The absence of C-peptide (proinsulin) immunoreactivity in multigranular bodies, i.e., in early morphological stages of lysosomal digestion, was compatible with the ready access and breakdown of C-peptide and/or proinsulin by lysosomal degrading enzymes, while the insulin crystallized in secretory granule cores remained relatively protected. However, in the final stage of lysosomal digestion, i.e., in residual bodies where the secretory granule core material is no longer present, insulin immunoreactivity became undetectable. Lysosomal digestion thus appears to be a normal pathway for insulin degradation in the pancreatic B-cell.
Keywords AnimalsC-Peptide/metabolismCell CompartmentationCytoplasmic Granules/metabolismImmunologic TechniquesInsulin/ metabolismIslets of Langerhans/ metabolism/ultrastructureLysosomes/metabolismMicroscopy, ElectronProinsulin/ metabolismRats
PMID: 6368567
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Other version: http://jcb.rupress.org/content/98/1/222.full.pdf
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ORCI, Lelio et al. Insulin, not C-peptide (proinsulin), is present in crinophagic bodies of the pancreatic B-cell. In: The Journal of cell biology, 1984, vol. 98, n° 1, p. 222-228. doi: 10.1083/jcb.98.1.222 https://archive-ouverte.unige.ch/unige:8948

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Deposited on : 2010-07-12

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