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  • 1980-1984  (2)
  • 1975-1979  (5)
  • Rat  (6)
  • Gomori-positive elementary granules  (1)
  • 1
    ISSN: 1432-0568
    Keywords: Neurosecretion ; Adrenalectomy ; Diabetes insipidus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of adrenalectomy on the amount of “Gomori-positive” neurosecretory material in the outer layer of the median eminence and in the supraoptico-hypophysial system was studied in normal Long-Evans rats and in Long-Evans rats heterozygous and homozygous for hypothalamic diabetes insipidus. In all non-adrenalectomized rats very few “Gomori-positive” granules were found in the outer median eminence layer. After adrenalectomy the amount of the granules increased markedly in normal Long-Evans rats and only slightly in Long-Evans rats heterozygous for diabetes insipidus. However, no augmentation of the granules occurred in homozygous diabetes insipidus rats. The amount of “Gomori-positive” substances demonstrable in the supraoptic and paraventricular nuclei, in the inner layer of the median eminence, and in the neural lobe of the hypophysis was less in rats heterozygous for diabetes insipidus than in normal Long-Evans rats and the smallest in homozygous diabetes insipidus rats. No differences in the amounts of the substances were observed between adrenalectomized and non-adrenalectomized animals. The findings suggest that the “Gomori-positive” granules occurring in the outer layer of the median eminence of adrenalectomized rats are of similar origin as those of the supraoptico-hypophysial system and represent a vasopressin-neurophysin-complex. The results support the concept that vasopressin is involved in the regulation of ACTH release.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0568
    Keywords: Corticotropin releasing factor ; Neurosecretion ; Hypophysis ; X-irradiation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In 195 female Wistar rats the influence of adrenalectomy, total body X-irradiation and dexamethasone treatment on the amount of CRF-granules in the external zone of the median eminence and “classical” neurosecretory material (NSM) in the internal zone of the median and in the posterior lobe of the hypophysis has been studied. In the normal rat only very few CRF-granules occur. 15 days after adrenalectomy increased amounts of CRF-granules but normal amounts of “classical” NSM are found. X-irradiation leads to a slight diminishment of “classical” NSM in normal rats. In adrenalectomized animals X-irradiation causes no changes in the amount of “classical” NSM but a marked decrease in the amount of CRF-granules. Application of dexamethasone from the 15th to 18th day after adrenalectomy enhances the augmentation of CRF-granules in irradiated and non-irradiated rats but does not influence the amount of “classical” NSM. The findings show that no correlation exists between the quantitative changes of CRF-granules and “classical” NSM under the experimental conditions used. Therefore it is to be assumed that the release of the two substances is regulated by different control mechanisms and that the substances have a different functional significance. The observations do not exclude the possibility that CRF-granules and “classical” NSM are biochemically identical.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0568
    Keywords: CRF-granules ; Sodium chloride ; Adrenalectomy ; Rat ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bilaterally adrenalectomized female SPF Wistar rats were given tap water containing various concentrations of sodium chloride to drink ad lib. After a survival period of 14 days the animals were killed by perfusion-fixation. Their brains were removed, fixed in pieric acid formalin solution and embedded in Paraplast. Serial sections of median eminence and hypophysial posterior lobe were cut and stained with crotonaldehyde-fuchsine. In the stained sections the amount of CRF-granules visible in the external zone of the median eminence, and the amount of “classical” neurosecretory material (NSM) occuring in the internal zone of the median eminence and in the posterior lobe of the hypophysis were estimated. After administration of drinking solutions to which 0%–1% sodium chloride were added, the amount of CRF-granules increased with increasing NaCl uptake, whereas the amount of “classical” NSM was not changed. Application of tap water containing 2% NaCl led to a marked decrease in the amount of “classical” NSM but did only slightly impair the amount of CRF-granules. From the findings it is concluded that 1. following bilateral adrenalectomy administration of sodium chloride inhibits the secretion of CRF-granules; 2. CRF-granules and “classical” NSM, although histochemical identical, have different functional significances; 3. the mechanisms regulating the secretion of CRF-granules are different from those controlling the release of “classical” NSM.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0878
    Keywords: CRF ; Vasopressin ; Adrenalectomy ; Rat ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In female Wistar rats the influence of adrenalectomy and NaCl administration on the amount of “classical” neurosecretory material (cNSM) in the supraoptico-hypophysial system and on vasopressin-like substance-containing granules (vlG) in the outer layer of the median eminence has been studied. In conjunction with appropriate sodium replacement, adrenalectomy induces an increase in the amount of vlG but does not alter the amount of cNSM. Administration of hypertonic saline diminishes cNSM but has no or only little influence on the amount of vlG. From the findings it is concluded that cNSM and vlG, in spite of their identical histochemical and immunohistochemical properties, have different functions. The functional significance of the vlG is discussed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 163 (1975), S. 503-508 
    ISSN: 1432-0878
    Keywords: Infundibulum ; Gomori-positive elementary granules ; Mammals ; Birds ; Fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary With the gallocyanine technique (Wittkowski, Bock and Franken, 1970) Gomori-positive substances of the infundibulum can be stained for light- and electron-microscopic examination. In various mammalian species, the size of Gomori-positive elementary granules in the outer layer is markedly different from that in the inner layer of the infundibulum. In general, the granules of the outer layer have less then half the diameter of those of the inner layer. In birds and fish, however, only small differences were found between the granules of both layers. The significance of the results is discussed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 185 (1977), S. 215-229 
    ISSN: 1432-0878
    Keywords: CRF-granules ; Adrenalectomy ; Hypothalamic lesions ; Rat ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Axons terminating in the outer layer of the median eminence of rats contain light microscopically visible granules. The granules are assumed to represent a corticotropin-releasing factor and, therefore, are called CRF granules. To find out whether neurons containing CRF-granules originate and run together with the neurons of the hypothalamus-neural lobe system (HNS), the effect of unilateral lesions in the HNS on the amount and distribution of CRF-granules was studied in bilaterally adrenalectomized rats. HNS lesions prevented the adrenalectomy-induced increase in CRF granules on the side of the lesion. Lesions outside the HNS or sham lesions did not influence the amount and distribution of the granules. The findings suggest that CRF-granules are located in terminals of neurons whose perikarya are situated in magnocellular hypothalamic nuclei. It can also be concluded that the axons of these neurons run within the HNS and do not decussate.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0878
    Keywords: Vasopressin ; Oxytocin ; Neurophysin ; Neurohypophysis ; Adrenalectomy ; Osmotic stress ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The influence of adrenalectomy and administration of hypertonic saline on the amount of vasopressin, oxytocin, and neurophysin contained in the median eminence and the neural lobe of rats was studied by means of the following methods: (i) morphometric and microphotometric analyses of aldehyde fuchsin-stained histological sections of the neurohypophysis; (ii) immunohistochemical demonstration of vasopressin, oxytocin, and neurophysin in the neurohypophysis, and (iii) radioimmunological measurement of vasopressin and oxytocin in extracts of the median eminence and the neural lobe. Adrenalectomy increases the amount of vasopressin and neurophysin in the external layer of the median eminence but does not change the content of oxytocin. It has no influence on the amount of vasopressin, oxytocin, and neurophysin demonstrable in the inner layer of the median eminence and in the neural lobe two weeks after the operation. Hypertonic saline markedly diminishes the vasopressin, oxytocin, and neurophysin content of the inner layer of the median eminence and the neural lobe but reduces only slightly, if at all, the amount of vasopressin and neurophysin in the outer layer of the median eminence. The findings support the concept that osmotic stress reduces only the vasopressin and oxytocin content of the hypothalamus-neural lobe system and has no or only little influence on the vasopressin content of the outer layer of the median eminence.
    Type of Medium: Electronic Resource
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