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  • Electronic Resource  (4)
  • 1975-1979  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 56 (1978), S. 71-79 
    ISSN: 1432-1440
    Keywords: ADH ; Angiotensin ; Bluthochdruck ; akutes Nierenversagen ; Vasopressin ; Angiotensin ; Hypertension ; Acute renal failure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Studies on the vasopressor role of the antidiuretic hormone arginine-vasopressin (AVP) in DOC hypertension, in two-kidney Goldblatt hypertension, and in spontaneous hypertension of rats, and during acute blood pressure elevation after intracerebroventricular injection of angiotensin II and in glycerol-induced acute renal failure of rats are reviewed. For the measurement of plasma AVP a radioimmunoassay has been developed. For this assay, a series of criteria has been met which allows the conclusion that, in plasma of rats, the antibody measures AVP only. For the blockade of vasopressor effects of AVP a specific antiserum has been used. On the basis of a series of control studies it has been concluded, but not proven that the antiserum lowers blood pressure exclusively by blockade of AVP. It could be shown that in the various animal models of hypertension and of acute blood pressure elevation AVP exerts systemic vasoconstriction when its plasma concentrations are elevated. In those models where the renin-angiotensin system played no role in blood pressure control, the height of blood pressure was closely related to the plasma AVP concentrations. When this relationship was compared with that obtained after the i.v. infusion or injection of AVP, a marked shift to the left became apparent. Hence, sensitization to the vasopressor effect of AVP had occurred, the factor of sensitization amounting to more than 1,000. It is concluded that AVP is not only an antidiuretic hormone but also a vasopressor hormone, and that any systemic vasopressor effect of AVP requires a mechanism of sensitization.
    Notes: Zusammenfassung Es wird eine zusammenfassende Darstellung gegeben über Untersuchungen zur vasopressorischen Wirkung von Arginin-Vasopressin (AVP) bei Ratten mit renalem, spontanem und DOC-induziertem Hochdruck, sowie beim akuten Blutdruckanstieg nach intracerebroventrikulärer Injektion von Angiotensin II und im akuten Nierenversagen. Zur Messung von Plasma-AVP wurde ein Radioimmunoassay entwickelt. Aufgrund einer Reihe von erfüllten Kriterien konnte geschlossen, jedoch nicht bewiesen werden, daß der verwendete Antikörper in Plasma-Extrakten ausschließlich AVP mißt. Zur Hemmung der vasopressorischen Wirkung von AVP wurde ein spezifisches AVP-Antiserum verwendet. Die Resultate einer Reihe von Kontroll-Versuchen erhärteten den Schluß, erbrachten jedoch nicht den Beweis, daß dieser Antikörper eine Blutdrucksenkung ausschließlich durch AVP-Blockade verursacht. Für die genannten Tiermodelle wurde gezeigt, daß AVP dann eine systemische Vasokonstriktion und damit einen erhöhten Blutdruck verursacht, wenn seine Plasma-Konzentrationen erhöht sind. In den Hochdruckmodellen, in welchen das Renin-Angiotensin-System keine Rolle in der Blutdruckregulation zu spielen scheint, besteht zwischen Blutdruckhöhe und der entsprechenden AVP-Plasmakonzentration eine enge quantitative Beziehung. Wenn diese Beziehung verglichen wird mit der entsprechenden Beziehung während AVP-Infusion im normotensiven Tier, so zeigt sich eine starke Linksverschiebung. Daraus geht hervor, daß in den verschiedenen Hochdruckmodellen eine Sensibilisierung auf die vasopressorische Wirkung des AVP stattfindet und zwar um ein Ausmaß, das den Faktor 1000 übersteigt. Aufgrund der dargestellten Befunde wird geschlossen, daß AVP nicht nur das antidiuretische Hormon ist, sondern auch ein vasopressorisches Hormon, und daß eine notwendige Voraussetzung für einen vasopressorischen Effekt von AVP ein Sensibilisierungs-Mechanismus ist.
    Type of Medium: Electronic Resource
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  • 2
    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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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Somatic cell and molecular genetics 5 (1979), S. 469-480 
    ISSN: 1572-9931
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Diphtheria toxin-resistance markers in two translational mutants, CH-RE1.22c, possessing no toxin-sensitive EF-2 (class IIa), and CH-RE1.32, with 50% toxin-sensitive and 50% toxin-resistant EF-2 (class IIb), behaved codominantly in somatic cell hybrids. There was no complementation in hybrids formed between the two resistant mutants. The mutant parents and their hybrids, except those formed by fusion of CH-RE1.32 and wild-type cells, grew in the presence of toxin. To explain these results we suggest that CHO-K1 cells possess two functional copies of the gene for EF-2 and that CH-RE1.22c and CH-RE1.32 represent the homozygous (R/R) and heterozygous (R/S) states of resistance at the EF-2 gene locus. The failure of hybrids formed between CH-RE1.32 and wild-type cells to grow in toxin is a gene dosage effect. Codominant class IIa translational resistance is a selectable marker for the isolation of hybrids. It can be combined with a second, recessive, marker to provide a cell which is a “universal hybridizer” (10).
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Somatic cell and molecular genetics 5 (1979), S. 453-468 
    ISSN: 1572-9931
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Variations in two general classes of diphtheria toxin-resistant mutants which may be selected from Chinese hamster ovary (CH0-K1) cells and the conditions for their selection are described. The resistance of class I mutants can be overcome with increasing concentrations of toxin. Their entire complement of EF-2 is susceptible to ADP-ribosylation by toxin. Class I includes those strains in which resistance resides at the level of the plasma membrane. The resistance of class II, translational, mutants cannot be overcome by high concentrations of toxin, as all, or a portion, of their EF-2 is insensitive to the action of diphtheria toxin and Pseudomonas exotoxin A. Adjustment of the concentration of toxin used to select resistant mutants can be used to regulate the class of mutant recovered. Metabolic cooperation between cells does not affect recovery of either class I or class II mutants. Resistance is stable in class I strains, but class IIb strains, which possess 50 % resistant and 50 % sensitive EF-2, display a transient high level of resistance which is retained for varying lengths of time following exposure to toxin. Class IIa strains, which possess 100% resistant EF-2, grow normally in saturating concentrations of toxin, but class IIb strains grow at a reduced rate. Evidence is presented which suggests that the gene for EF-2 is functionally diploid in CH0-K1 cells.
    Type of Medium: Electronic Resource
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