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  • 1
    Electronic Resource
    Electronic Resource
    Differential routing of coexisting neuropeptides in vasopressin neurons (2003)
    Oxford, UK : Blackwell Science, Ltd
    European journal of neuroscience 17 (2003), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The functional implications of intraneuronal coexistence of different neuropeptides depend on their respective targeting to release sites. In the rat hypothalamic magnocellular neurons, we investigated a possible differential routing of the coexpressed galanin and vasopressin. The respective location of proteins and messengers was assessed with double immunogold and in situ hybridization combining confocal and electron microscope analysis. The various populations of labelled granules were quantitatively compared in three subcellular compartments: perikarya, local processes and posthypophyseal nerve endings. Three subpopulations of granules were detected in all three compartments, but their respective amount showed significant differences. Galanin alone was immunolocalized in some secretory granules, vasopressin alone in others, and both peptides in a third subpopulation of granules. The major part of the granules containing vasopressin, either alone or in association with galanin, is found in neurohypophyseal nerve endings. In contrast, galanin single-labelled granules represent the most abundant population in dendritic processes, while double-labelled granules are more numerous in perikarya. This indicates a preferential distribution of the two peptides in the different compartments of magnocellular neurons. Furthermore, galanin and vasopressin messenger RNAs were detected at different domains of the endoplasmic reticulum, suggesting that translation might also occur at different locations, thus leading to partial segregation of galanin and vasopressin cargoes between two populations of secretory granules. The present study provides, for the first time in mammals, evidence suggesting that galanin and vasopressin are only partly copackaged and undergo a preferential targeting toward dendrites or neurohypophysis, suggesting different functions, autocrine/paracrine and endocrine, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2002.00162.x-i1
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  • 2
    Electronic Resource
    Electronic Resource
    Differential routing of coexisting neuropeptides in vasopressin neurons (2003)
    Oxford, UK : Blackwell Science, Ltd
    European journal of neuroscience 17 (2003), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The functional implications of intraneuronal coexistence of different neuropeptides depend on their respective targeting to release sites. In the rat hypothalamic magnocellular neurons, we investigated a possible differential routing of the coexpressed galanin and vasopressin. The respective location of proteins and messengers was assessed with double immunogold and in situ hybridization combining confocal and electron microscope analysis. The various populations of labelled granules were quantitatively compared in three subcellular compartments: perikarya, local processes and posthypophyseal nerve endings. Three subpopulations of granules were detected in all three compartments, but their respective amount showed significant differences. Galanin alone was immunolocalized in some secretory granules, vasopressin alone in others, and both peptides in a third subpopulation of granules. The major part of the granules containing vasopressin, either alone or in association with galanin, is found in neurohypophyseal nerve endings. In contrast, galanin single-labelled granules represent the most abundant population in dendritic processes, while double-labelled granules are more numerous in perikarya. This indicates a preferential distribution of the two peptides in the different compartments of magnocellular neurons. Furthermore, galanin and vasopressin messenger RNAs were detected at different domains of the endoplasmic reticulum, suggesting that translation might also occur at different locations, thus leading to partial segregation of galanin and vasopressin cargoes between two populations of secretory granules. The present study provides, for the first time in mammals, evidence suggesting that galanin and vasopressin are only partly copackaged and undergo a preferential targeting toward dendrites or neurohypophysis, suggesting different functions, autocrine/paracrine and endocrine, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2003.02472.x
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  • 3
    Electronic Resource
    Electronic Resource
    An ultrastructural study of sites of granule extrusion in the anterior pituitary of the rat (1971)
    Springer
    Cell & tissue research 115 (1971), S. 501-507 
    Details
    ISSN: 1432-0878
    Keywords: Hormonal release ; Exocytosis ; Basement membrane ; Adenohypophysiotropic factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Secretory granule extrusion in cells of the rat anterior pituitary was studied by electron microscopy. After appropriate stimulation, corticotrophs, somatotrophs and thyrotrophs showed both “in vivo” and “in vitro” (tissue culture) the extrusion of granules by reverse pinocytosis (exocytosis). In contrast, this phenomenon is not observed in gonadotrophs. Granule extrusion takes place only at those parts of the cell which are in contact with the basement membrane. This directed release seems to favor a quicker diffusion of hormones to the circulatory system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335716
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  • 4
    Electronic Resource
    Electronic Resource
    Le réseau des cellules folliculo-stellaires et les follicules de l'adénohypophyse du rat (Pars distalis) (1972)
    Springer
    Cell & tissue research 129 (1972), S. 328-369 
    Details
    ISSN: 1432-0878
    Keywords: Anterior pituitary ; Follicular and stellate cells ; “Réseau folliculostellaire” ; Chromophobe cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Dans l'hypophyse du rat, la microscopie électronique permet de mettre en évidence à l'intérieur de tous les cordons épithéliaux de la pars distalis un réseau de cellules agranulaires: les cellules stellaires et folliculo-stellaires, satellites des cellules granuleuses hormonogènes. Les cellules de ce réseau se caractérisent à la fois par la multiplicité de leurs prolongements et par leur organisation autour de cavités pour la plupart submicroscopiques, «les follicules». Les cellules folliculo-stellaires correspondent à une partie des cellules chromophobes de la microscopie photonique. La fente hypophysaire, par de nombreux caractères, semble faire partie de ce système folliculo-stellaire, dont elle pourrait représenter une région privilégiée par sa situation, ses dimensions et son contenu. L'existence des cellules folliculo-stellaires dans un grand nombre d'espèces, leurs caractères cytologiques hautement différenciés, leurs relations étroites avec le milieu intérieur interstitiel et leurs modifications en fonction de l'âge et des conditions expérimentales permettent de penser qu'elles sont étroitement attachées à la fonction glandulaire.
    Notes: Summary Electron microscopic investigation of the rat anterior pituitary reveals, throughout the whole pars distalis, a cellular network composed of agranular cells. These cells, the stellate and folliculo-stellate cells, are satellites of the granulated secretory cells. The cells of the network are characterized both by their multiple cytoplasmic processes and by their organization around cavities, most of them submicroscopic, the “follicles”. Those cells probably represent a large part of the “chromophobe” cells previously observed by light microscopy. On account of several characters, the pituitary cleft seems to be related to the “réseau folliculo-stellaire” and could be a peculiar part of this system because of its localization, size and contents. The “réseau folliculo-stellaire” is present in numerous species, showing a typical and differentiated cytology, and close relationships with the interstitial medium. Owing to its morphology and to modifications according to age and experimental conditions, this network seems to be a system intimately involved in the glandular function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307293
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  • 5
    Electronic Resource
    Electronic Resource
    Structural and functional differences between prolactin cells from the inner and outer zones of the male rat anterior pituitary (1996)
    Springer
    Cell & tissue research 284 (1996), S. 247-259 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Prolactin cells ; Anterior pituitary (inner and outer zones) ; Secretory activity ; Ultrastructural immunohistochemistry ; Standard and ultrastructural reverse hemolytic plaque assays ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The aim of this study was to compare the ultrastructure of prolactin cells in the inner and outer zones of the male rat anterior pituitary, and to relate their morphological features to their secretory activity, by means of standard and ultrastructural reverse hemolytic plaque assays (RHPA). The immuno-ultrastructural study showed that in the inner pituitary small-granulated cells represented 52% of the prolactin cells, there being only 5% with large granules, whereas the prolactin cells with large granules accounted for 52% in the outer zone, with only 7% being small-granulated. Percentages of cells with intermediate-sized granules were 43% and 41%, respectively. Analysis of RHPA data revealed that, under basal conditions, prolactin cells secreted more actively in the inner zone than in the outer zone. Stimulation with thyrotropin-releasing hormone or KCl treatment increased the percentage of secretors and the sizes of hemolytic plaques in both zones. However, in response to thyrotropin-releasing hormone, the increase in number of secretors was always higher in the outer zone, whereas the enlargement of plaque sizes was greater for the ”inner” cells. These findings are in favor of the small-granulated cells, which predominate in the inner zone, being in a stage of active secretion and responsiveness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050585
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  • 6
    Electronic Resource
    Electronic Resource
    Subcellular distribution of laminin and prolactin in stimulated and blocked prolactin cells in the pituitary of lactating rats (1988)
    Springer
    Cell & tissue research 254 (1988), S. 617-627 
    Details
    ISSN: 1432-0878
    Keywords: Laminin ; Prolactin ; Pituitary gland, pars anterior ; Lactation (suckling, weaning) ; Ultrastructural immunocytochemistry ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Laminin (LAM), a glycoprotein component of basement membranes, has been previously detected within several subcellular compartments of prolactin (PRL) cells in the pituitary gland. The present work was aimed at comparing the subcellular localization of PRL, a specific secretory product, with that of LAM, in relation to the secretory activity of PRL cells. LAM and PRL were located in parallel, by ultrastructural immunocytochemistry, in PRL cells of lactating female Wistar rats, either stimulated by suckling, or blocked by weaning, or reactivated by suckle following short-term weaning. Variations in physiological conditions were correlated with a redistribution of PRL immunoreactivity within morphologically modified compartments. The Golgi apparatus became hypertrophied, and PRL impressively accumulated within saccules of the Golgi stacks of blocked cells. On the contrary, no apparent changes occurred in LAM distribution, at least at the Golgi level. Only a slight increase of LAM immunoreactivity was observed in rough endoplasmic reticulum after a long weaning period. PRL could be detected in most of the secretory granules and particularly in forming elements, whereas LAM was observable at the peripheral edge of some mature granules. Such a labeling was not markedly influenced by the physiological state. The prominent structures, indicative of crinophagic activity, characteristic of blocked cells, contained masses of dense material, which were always immunopositive with antibodies to PRL, but never to LAM. These observations could suggest that, in PRL cells, intracellular transport and exportation of LAM are controlled by mechanisms independent from those involved in the regulation of PRL secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226512
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