Abstract
The subcellular distribution of p65 (synaptotagmin), of the endoproteases PC1 and PC2 and of secretoneurin was studied in bovine posterior pituitary by differential and density gradient centrifugation. All these peptides were found to be present in the neurosecretory granules (large dense core vesicles). p65 can therefore participate not only in exocytosis from small synaptic vesicles but also from large dense core vesicles. Secretoneurin is a peptide derived from secretogranin II. Processing of the propeptide apparently occurs during axonal transport of the large dense core vesicles and is complete in the posterior pituitary. Thus, stimulation of the hypothalamic magnocellular neurons can lead to the release of this newly characterized, functional neuropeptide.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Aspartic Acid Endopeptidases / analysis*
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Calcium-Binding Proteins*
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Cattle
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Cell Fractionation
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Centrifugation, Density Gradient
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Chromatography, High Pressure Liquid
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Cytoplasmic Granules / chemistry
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Exocytosis
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Immunoblotting
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Membrane Glycoproteins / analysis*
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Nerve Tissue Proteins / analysis*
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Neuropeptides / analysis*
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Pituitary Gland, Posterior / chemistry*
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Pituitary Gland, Posterior / ultrastructure
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Proprotein Convertase 2
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Proprotein Convertases
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Secretogranin II
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Subcellular Fractions / chemistry*
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Subtilisins / analysis*
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Synaptotagmin I
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Synaptotagmins
Substances
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Calcium-Binding Proteins
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Membrane Glycoproteins
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Nerve Tissue Proteins
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Neuropeptides
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Secretogranin II
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Synaptotagmin I
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Synaptotagmins
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secretoneurin
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Proprotein Convertases
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Subtilisins
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Proprotein Convertase 2
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Aspartic Acid Endopeptidases