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  • Rat  (4)
  • Springer  (4)
  • Annual Reviews
  • National Academy of Sciences
  • Springer Science + Business Media
  • 1980-1984  (4)
  • 1980  (4)
Collection
Publisher
  • Springer  (4)
  • Annual Reviews
  • National Academy of Sciences
  • Springer Science + Business Media
Years
  • 1980-1984  (4)
Year
  • 1
    ISSN: 1432-0878
    Keywords: Rat ; Preovulatory follicle ; Ultrastructure ; Degeneration ; Atresia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To identify and describe ovarian follicles committed to undergo follicular degeneration (atresia), immature rats were primed with pregnant mare serum gonadotropin (PMSG). After PMSG treatment, preovulatory follicles develop but subsequently degenerate. Prior to the appearance of pyknotic nuclei (Stage I of atresia), degenerative changes were observed in focal areas of the granulosa cell layer. These changes include “blebbing” of the cytoplasm and alterations in the shape of the granulosa cells. The appearance of these degenerative changes coincides with a decrease in ovarian concentrations of estradiol and testosterone. Since estrogens and androgens maintain the follicle, the decline in estradiol and testosterone could be responsible for the further degenerative alterations that lead to complete deterioration of the preovulatory follicle. In Stage I atretic follicles, lysosome-derived autophagic vacuoles develop and macrophages invade both the thecal and granulosa cell layers. The combined actions of the autophagic vacuoles and macrophages could destroy both the granulosa-cell and thecal layers and thereby transform the preovulatory follicle into an ovarian cyst.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Sympathetic innervation ; Renin-angiotensin system ; Electron microscopy ; Fluorescence microscopy ; Tupaia belangeri ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It has previously been reported that the primitive primate Tupaia belangeri develops a renal failure when exposed to psychosocial stress. In order to learn if this high susceptibility to stress of the Tupaia kidney can be correlated with morphological and functional parameters of the Juxtaglomerular apparatus (JGA) and the renin-angiotensin system, comparative experiments were performed on Tupaia and rat. Our results reveal an outstandingly high potency of the JGA and the renin-angiotensin system in Tupaia as evident from the following findings: The Tupaia JGA contains a great number of epithelioid cells abounding in renin granules (electron microscopy). The renin content of the Tupaia kidney is considerably higher than in the rat (radio-immunoassay). The sympathetic innervation of the kidney and especially of the JGA is abundant in Tupaia (fluorescence and electron microscopy). Catecholamine contents of the kidney and other organs are significantly higher in Tupaia than in rats (spectrophotofluorometry). Our results support the previously developed concept of a potent intrarenal neuroendocrine interaction at the JGA level favouring, under certain conditions of social stress, the development of acute renal failure in Tupaia belangeri.
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  • 3
    ISSN: 1432-0878
    Keywords: AVT ; LHRH ; α-MSH ; Somatostatin ; Pineal Gland ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Resumé En utilisant des anticorps contre l'AVT, l'α-MSH, le LHRH et la somatostatine, des cellules épiphysaires du Rat ont été immunocytochimiquement colorées. Tous ces anticorps colorent les mêmes cellules. Ces cellules réagissent également quand un anticorps est utilisé contre la fraction épiphysaire UMO5R, fraction qui est douée de propriétés antigonadotropiques in vivo. Il a également été montré que le nombre des cellules immunoréactives était plus important dans la pinéale du jeune rat que dans celle de l'adulte. La comparaison des résultats obtenus avec différents anticorps et l'étude des propriétés de ces anticorps aprés absorption sur différents peptides ou sur différentes fractions épiphysaires, a permis de conclure que les réactions obtenues dans la pinéale du rat n'étaient que la conséquence d'une réaction croisée de ces anticorps avec une/des substance(s) inconnue(s) synthétisée(s) par la pinéale elle-même. La nature endocrine possible de cette substance qui serait chimiquement apparenté aux fractions épiphysaires Mouton UMO5R et Prot. 4, est discutée. Drs. B.L. Baker (Ann Arbor, Mich., USA), M.P. Dubois (Nouzilly, France), J. De Mey (Beerse, Belgium), J.D. Fernstrom (Cambridge, Mass., USA.), H. Goos (Utrecht, The Netherlands), B. Kerdelhué (Gif-sur-Yvette, France) and A.G.E. Pearse (London, U.K.) are also acknowledged for their gifts of various antibodies
    Notes: Summary Using antibodies against AVT, α-MSH, LHRH and somatostatin, immunoreactive cells were detected in the rat pineal gland. All of these antibodies stain the same cells, which also react immunocytochemically when an antibody against the UMO5R sheep pineal fraction, a fraction that presents antigonadotropic properties in vivo, is used. Relatively more immunoreactive cells are present in the pineals of young rats than in the pineals of adult animals. Comparison of the results obtained with different potent antibodies against each of the peptides, and a study of the staining properties of the antibodies in the pineal after solid phase adsorption to different peptides or to different sheep pineal fractions, led to the proposal that the immunoreactivity found in the rat pineal is not due to the presence of AVT, α-MSH, LHRH or somatostatin, but to a cross-reaction of each of these antibodies with (an) unidentified compound(s). This compound is synthetized in the pineal gland, as was demonstrated using cultured pineals. The UMO5R and the Prot. 4 fractions of the sheep pineal seem to be chemically related to this unknown compound, the possible endocrine nature of which is discussed.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 211 (1980), S. 175-177 
    ISSN: 1432-0878
    Keywords: Parietal cell ; Stomach ; Circadian rhythm ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gastric parietal cells of rats maintained under standardized conditions and fed ad libitum were examined by electron microscopy at 6 time points of the 24-h day. Morphometric determinations were made on 4 cell characteristics. The volume density of secretory canaliculi was maximal at the mid-dark sampling point and decreased during the light phase; a secondary peak was seen 1 h before the onset of darkness. The surface density of microvesicles and RER fluctuated inversely with the pattern displayed by secretory canaliculi. The number of multivesicular bodies per cytoplasmic area exhibited a single peak, 1 h after the onset of darkness. It was further noted that parietal cells in the necks and bases of glands differed morphologically and that their organelle populations varied at individual circadian rates.
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