Riassunto
L’ultrastructure des granules β du pancréas endocrinien a été examinée en divers mammiferi mediante l’impiego, per la fissazione, di glutaraldeide, tetrossido di osmio e permanganato di potassio. Il nucleo dei granuli ha struttura globulare, tubulare o cristalloide. La sostanza proteica viene conservata dalla fissazione con glutaraldeide e « maschera » l’ultrastruttura dei granuli β, la quale diviene ottimamente visibile dopo fissazione in osmio. Gli AA. ritengono che l’ultrastruttura del nucleo dipenda dall’organizzazione molecolare della « sostanza vettrice » alla quale l’insulina si trova legata. La liberazione dell’ormone si accompagna a modificazioni del nucleo, dell’« alone » e, soprattutto, della membrana elementare del granulo.
Résumé
L’ultra-structure des granules β du pancréas endocrinien a été examinée en divers mammifères moyennant l’utilisation (pour la fixation) de glutaraldéhyde, de tétraoxyde d’osmium et de permanganate de potasse. Le nucléus des granules présente une structure globulaire, tubulaire ou cristalloïde. La substance protéique est protégée de la fixation par le glutaraldéhyde et « masque » l’ultrastructure des granules β, laquelle devient très bien visible après la fixation en osmium. Les auteurs estiment que l’ultrastructure du nucléus dépend de l’organisation moléculaire de la substance « porteuse » à laquelle l’insulíne se trouve liée. La libération de l’hormone s’accompagne de modifications du nucléus, de « l’halo » et surtout de la membrane élémentaire du granule.
Resumen
Se ha examinado la ultraestructura de los granulos β del páncreas endocrino de diversos mamíferos utilizando para la fijación glutaraldehido, tetróxido de osmio y permanganato de potasio. El núcleo de los gránulos tiene estructura tubular, globular o cristaloide. La substancia proteica se conserva por medio de la fijación con glutaraldehido y « oculta » la estructura de los gránulos β, la cual se puede ver optimamente tras la fijación con osmio. Los autores opinan que la estructura del núcleo depende de la organización molecular de la « substancia vector » con la que la insulina está vinculada. La liberación del hormón coincide con modificaciones del núcleo, del « halón » y, sobre todo, de la membrana elemental.
Zusammenfassung
Die Ultrastruktur der β-Granula des endokrinen Pankreas wurde bei verschiedenen Säugetierarten mittels Fixierung in Glutaraldehyd, Osmiumtetroxyd und Kaliumpermanganat untersucht. Der Kern der Granula hat globuläre, tubuläre oder krystalloide Struktur. Die Eiweiss-Substanz wird mittels Glutaraldehyd erhalten und « maskiert » die Ultrastruktur der β-Granula. Diese kann am besten nach Osmiumfixierung beobachtet werden. Verfasser nehmen an, dass die Ultrastruktur des Granulumkerns von der molekulären Organisation der « Trägersubstanz » abhängt, an welche des Insulin gebunden ist. Die Freisetzung des Hormons geht mit Veränderungen sowohl am Kern als auch am « Hof » und an der Elementarmembran einher.
Summary
The ultrastructure of the β-granules of the endocrine pancreas in different mammals has been investigated by applying fixation with glutaraldehyde, osmium tetroxide and potassium permanganate. The core of the granules has a globular, tubular and crystalloid structure. The protein substance is preserved by fixation with glutaraldehyde and it ‘masks’ the ultrastructure of β-granules. The ultrastructure of β-granules can best be observed after osmium fixation. The authors consider the ultrastructure of the core to be dependent on the molecular organization of the ‘carrier substance’ to which insulin is bound. Insulin release is accompanied by changes both in the granule core and in the ‘halo’, and especially in the elementary membrane.
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Traduzione a cura di G. U.
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Petkov, P., Donev, S. The problem of β-granule ultrastructure in the endocrine pancreas. Acta diabet. lat 10, 54–88 (1973). https://doi.org/10.1007/BF02590652
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DOI: https://doi.org/10.1007/BF02590652