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  • Procion yellow  (2)
  • Cancer  (1)
  • 1
    ISSN: 1432-1106
    Keywords: Parvocellular neurons ; Intracellular recordings ; Procion yellow ; Estrogen ; Humoral control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracellular recordings and injections of procion yellow (PY) were made in parvocellular neurons in hypothalamic slices of female guinea pigs. Eighty-five neurons, with an average resting membrane potential of -35 mV, were recorded in the arcuate (ARC) ventromedial (VM), and in the cellpoor zones between the ARC and VM. Eleven of the ARC neurons and four neurons from the cell-poor zone could be driven antidromically by median eminence (ME) stimulation, nine other neurons from the three areas could be driven orthodromically by stria terminalis (ST) stimulation. Twenty-eight parvocellular neurons were tested with 17 β-estradiol (E2), which was applied in the bathing medium as the free steroid. Eleven neurons (nine ARC and two cell-poor-zone neurons) were hyperpolarized 2 to 24 mV by 10−10 M E2 concentrations. 10−8 M estrone concentration was without effect on three of these cells. Through the intracellular injection of PY, the estrogen-sensitive neurons (N = 11) were identified as small fusiform cells with few dendrites. Spine-like appendages were found on only one of these cells. None of the larger pyramidal-like neurons of these areas responded to the application of E2.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 34 (1979), S. 107-116 
    ISSN: 1432-1106
    Keywords: Parvocellular hypothalamic neurons ; Neurosecretion ; In vitro preparation ; Procion yellow ; Intracellular
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the in vitro slice preparation intracellular recordings and injections of procion yellow (PY) were made in neurons of the hypothalamus. Of these neurons, one medial preoptic-anterior hypothalamus (MPO-AH) and four arcuate-ventromedial hypothalamus (ARC-VM) neurons were driven by electrical stimulation of the median eminence area (ME). Two other MPO-AH and five other ARC-VM neurons were driven by stimulation of the stria terminalis (ST). On the basis of the PY injections two morphologically distinct cell types were delineated: a larger multipolar cell type with a polygonal perikaryon was found with equal frequency in the MPO-AH and the ARC-VM. A smaller fusiform cell type was encountered mainly in the ARC-VM. On the secondary dendrites of both cell types spine-like appendages were seldom seen, but dendritic swellings were common. Some of the dendrites projected to capillaries in both areas and presumably contacted them. The axons were usually tortuous and could only be traced a short distance.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Reproduktionsmedizin 15 (1999), S. 173-178 
    ISSN: 1434-808X
    Keywords: Schlüsselwörter Pestizide ; Phytoestrogene ; Plastik ; Umwelt ; Karzinome ; Key words Pesticides ; Insecticides ; Environment ; Cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The definition of endocrine disrupters is not very sharp. At present all non-physiologic substances which bind to steroid receptors, are defined as endocrine disrupters of which the best studied are estrogenic in nature. Many pesticides or insecticides or their metabolites have estrogenic activity and pollute our surface water. Here they may cause severe estrogenization of aquatic life. Only traces of these substances are demonstrable in drinking water. On the other hand, weak estrogens present in plastic ware may be ingested by men and therefore be potentially harmful for human health. On the other hand, many plants produce socalled‚hyto-estrogens’, particularly soy products are rich in phyto-estrogens but their high consumption in Asian populations are most likely the reason for reduced occurrence of breast cancer. Many plant extracts used for human medication also contain phyto-estrogens and are beneficial in the treatment of climacteric complaints. Hence, not all endocrine disruptors must be harmful to human health, in fact, some of them (clearly phyto-estrogens) may have beneficial effects.
    Notes: Zusammenfassung Die Definition für „endocrine disrupter“ ist sehr unscharf. Zur Zeit werden alle körperfremden Substanzen, welche an Steroidrezeptoren binden oder diese inhibieren, als endocrine disrupters betrachtet. Die meisten Grundlagen und klinischen Studien beschäftigen sich mit estrogenen Wirkungen von endocrine disrupters. Viele Pestizide und Insektizide sowie deren Metabolite haben estrogene Wirkungen und kommen naturgemäß in recht hohen Konzentrationen in unsere Oberflächengewässer. Hier üben sie in zahlreichen aquatischen Spezies femininisierende Wirkungen aus. Das Trinkwasser für menschlichen Gebrauch stammt überwiegend aus dem Grundwasser, wo diese Xenoestrogene in nicht nennenswertem Umfang nachgewiesen wurden. Für die menschliche Gesundheit dagegen können Phthalate und Bisphenole, ebenfalls schwache Estrogene, eine Rolle spielen. Sie werden in der Verpackungsindustrie bei der Plastikherstellung in großen Mengen eingesetzt. Eine weitere Quelle für Xenoestrogene stellen Pflanzen dar. Fast jede Pflanze produziert Isoflavone in mehr oder weniger großen Mengen, welche ebenfalls sogenannte Phytoestrogene sind. Besonders reich an Phytoestrogenen sind Sojaprodukte. Die Tatsache, daß asiatische Populationen, deren Proteingehalt überwiegend durch Sojaprodukte gedeckt wird, weniger Mammakarzinome entwickeln, hat zu der Annahme geführt, daß diese Phytoestrogene die Mammakarzinomentwicklung hemmen. Andererseits sind die aus Industriechemikalien beschriebenen Xenoestrogene in höheren Konzentrationen bei Patientinnen mit Mammakarzinom nachgewiesen worden. Die Beschreibung eines zweiten Estrogenrezeptortypen und zahlreicher Splicingvarianten kann möglicherweise organselektive Wirkungen von Xenoestrogenen verständlich machen. Phytoestrogene kommen in zahlreichen Pflanzenextrakten vor, die zur Therapie klimakterischer Beschwerden Einsatz finden.
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