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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructure of the adenohypophysis in the teleost Poecilia latipinna (1975)
    Springer
    Cell & tissue research 161 (1975), S. 239-261 
    Details
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Teleosts (Poecilia, latipinna) ; Cell types ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the sailfin molly, Poecilia latipinna, seven morphological endocrine celltypes could be distinguished with the electron microscope. Each of these was identified with one of the seven cell-types distinguished with the light microscope, to most of which endocrine functions have previously been allocated. Corticotrophs and prolactin cells form the rostral pars distalis, and the proximal pars distalis consists of an outer layer of gonadotrophs and an inner zone containing growth hormone cells and thyrotrophs. The pars intermedia contains two cell-types, of uncertain function. Stellate cells (interstitial cells) occur throughout the adenohypophysis, but are most numerous and prominent in the rostral pars distalis. The inner proximal pars distalis contains a cell-type not previously distinguished in this species with the light microscope, the Z-cell, which could be aminergic. The ultrastructural features of each cell-type are described in detail, and discussed in comparisons with the homologous cells described in other teleosts. There is good agreement for different teleosts in the ultrastructural details of each cell type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220372
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Quantitative ultrastructural evidence of alterations in prolactin secretion related to external salinity in a teleost fish (Poecilia latipinna) (1977)
    Springer
    Cell & tissue research 185 (1977), S. 129-145 
    Details
    ISSN: 1432-0878
    Keywords: Prolactin cells ; Adenohypophysis ; Teleost (Poecilia latipinna) ; Salinity ; Morphometry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative ultrastructural morphometric studies were made on the prolactin cells of Poecilia latipinna adapted to freshwater (FW), one-third seawater (1/3 SW) and full-strength seawater (SW), and at various times after transfers between 1/3 SW and FW. In fully-adapted fish the rates of prolactin (PRL) synthesis and PRL release are inversely related to environmental salinity. During adaptation to a new salinity the two rates are temporarily uncoordinated, with release increasing or decreasing more readily than synthesis. Synthesis appears to take 30 h or longer to come into balance with the increased release rate following transfer from 1/3 SW to FW, and 72 h or longer to adjust to the reduction in release rate that follows the reverse transfer. The excess PRL granules that accumulate in the latter situation appear to be removed by lysosomal digestion. As in other teleosts, in fish adapted to the external medium the size of the stored PRL granules is inversely related to external salinity, but this relationship breaks down during adaptation to a new salinity. The stellate cells which penetrate between the PRL cells are more prominent, more extensively ramified, and appear more metabolically active in FW-adapted fish than in the other groups. These cells seem to be closely related in function to the secretory activity of the PRL cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226674
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructure of the neurohypophysis of the teleost Poecilia latipinna in relation to neural control of the adenohypophysial cells (1977)
    Springer
    Cell & tissue research 185 (1977), S. 409-433 
    Details
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Teleost (Poecilia latipinna) ; Axon types ; Hypothalamic control ; Morphometry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the neurohypophysis of Poecilia latipinna (green molly, sailfin molly) was studied with the electron microscope. Profile diameters of neurosecretory granules in the non-myelinated neurohypophysial nerve fibres were measured and mathematically corrected for error due to section thickness. Six different types of nerve fibres could be distinguished by statistical classification of their granules and by other ultrastructural features. One fibre-type (type B) contained granules with a mean diameter of 85 nm, and the other five types (types Ala, Alb, A2, A3 and A4) all contained granules with mean diameters greater than 100 nm. Synaptic contacts were observed between type B fibres and all the adenohypophysial cell-types, although in the case of the ACTH cells the synapses were separated from the cell membrane by a continuous double basement membrane. Type A fibres were observed to contact the cells of the proximal pars distalis and pars intermedia, but did not form synapses. However, synapses occurred between type A fibres and pituicytes, and between type A fibres and the pericapillary basement membrane in the interior of the neurohypophysis. The possible roles of the different types of nerve fibres in controlling the adenohypophysial cells are discussed in the context of evidence from other teleosts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220300
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    Paper (German National Licenses)
    Fulltext
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