Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Identification of Glucagon Receptors in Rat Retina (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 54 (1990), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In this study, we characterize the glucagon receptors on rat retinal particulate preparations. The specific binding of 125I-glucagon was saturable and reversible. Apparent equilibrium conditions were established within 30–45 min. Analysis of binding data is compatible with the existence of two classes of binding sites: a high-affinity class with a KD of 7 ± 0.8 nM and a Bmax of 2.3 ± 0.2 pmol/mg of protein and a low-affinity class with a KD of 84.4 ± 2.5 nM and a Bmax of 16.5 ± 2.3 pmol/mg of protein. The 125I-glucagon binding to retinal particulate preparation was not inhibited by 1 μM concentrations of insulin, atrial natriuretic factor, angiotensin II, somatostatin, and vasoactive intestinal peptide. However, synthetic human pancreatic growth hormone-releasing factor, hGRF-44, inhibited binding, although the concentration required for half-maximal displacement was 10-fold higher than that for native glucagon. Glucagon binding was GTP sensitive. Inclusion of 0.1 mM GTP in the binding assay produced an increase in the concentration of unlabeled glucagon required for half-maximal displacement of 125I-glucagon, from 23 to 220 nM. Glucagon stimulated adenylate cyclase formation in retinal particulate preparations. The concentration of glucagon required for half-maximal activation of retinal adenylate cyclase was 16.2 nM. These results suggest that glucagon may play a role as a neurosignal transmitter in rat retina.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1990.tb01953.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Identification and Characterization of Endothelin Receptor Subtype B in Rat Retina (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 61 (1993), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The presence of immunoreactive (IR) endothelin (ET)-1 and ET-1 receptors in rat retina has been studied by radioimmunoassay and receptor assay, respectively. The specific binding of 125I-ET-1 to rat retinal particulate preparations was saturable. Apparent equilibrium conditions were established within 120–140 min. Scatchard analysis of binding data indicated a single class of high-affinity binding sites with a KD of 35 ± 11 pM and a Bmax of 168 ± 60 fmol/mg of protein. 125I-ET-1 binding to retinal particulate preparations was not inhibited by 1 μM concentrations of somatostatin, atrial natriuretic factor, brain natriuretic peptide, thyroid-stimulating hormone, growth hormone, or insulin. The three endothelin isoforms, ET-1,-2, and-3, had similar affinity for the receptor. Cross-linking of 125I-ET-1 to retinal particulate preparations with disuccinimidyl suberate resulted in the labeling of two bands with apparent molecular masses of 52 and 34 kDa. We have established a highly sensitive and specific radioimmunoassay for ET-1. The concentration of IR-ET-1 in rat retina was 35 ± 10 fmol/g wet weight. The demonstration of specific high-affinity ETB receptors and the presence of IR-ET-1 suggest that the peptide may act as a neurotransmitter or neuro-modulator in the retina.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1993.tb03627.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Somatostatin analogs which inhibit glucagon and growth hormone more than insulin release
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 74 (1977), S. 630-636 
    Details
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0006-291X(77)90349-7
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Antral gastrin-producing G-cells and somatostatin-producing D-cells in peptic ulcer (1987)
    Springer
    Virchows Archiv 410 (1987), S. 165-171 
    Details
    ISSN: 1432-2307
    Keywords: Gastrin ; Somatostatin ; Peptic ulcer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The number of G cells and D cells per area unit and the G cell/D cell ratio was studied in control subjects and patients with duodenal or gastric ulcer. A great inter-individual variation in the population density of both types of cells was observed in the three groups studied. G cell density was significantly decreased in both duodenal and gastric ulcer patients, when compared with controls; whereas no difference in G cell density was seen between duodenal ulcer patients and gastric ulcer patients. However, D cell density was significantly decreased in duodenal ulcer patients when compared with control subjects and gastric ulcer patients. In this latter group, D cell density was also lower than in control subjects. A significant positive linear correlation between G cell number and D cell number was found in the three groups studied. The G cell/D cell ratio was significantly increased in duodenal and gastric ulcer patients when compared with controls. This was mainly due to a decrease in D cell numbers. It is concluded that a local deficit in antral D cells in patients with peptic ulcer may favor the pathogenesis of ulcer disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00710821
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Changes in the density and localisation of endothelin receptors in the early stages of rat diabetic retinopathy and the effect of insulin treatment (2000)
    Springer
    Diabetologia 43 (2000), S. 773-785 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Endothelin, endothelin receptors, insulin, retinopathy.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. The endothelin system (ET system) has been implicated in the retinal blood flow abnormalities that precede the onset of diabetic retinopathy. This study was undertaken to assess whether the density and localisation of both the immunoreactive endothelin-1 and endothelin receptors in rat retina change in the early stages of diabetes and the insulin treatment would affect those changes.¶Methods. Untreated streptozotocin-diabetic, insulin-treated streptozotocin-diabetic and age-matched control rats were killed 15, 45 and 90 days after the induction of diabetes. Binding assays were used to determine the density and proportion of endothelin receptors in neural retinal membranes. Localisation of endothelin receptors and immunoreactive endothelin-1 were analysed by microautoradiography and immunohistochemistry, respectively.¶Results. Fifteen days after the induction of diabetes, the neural retinal membranes of untreated streptozotocin-diabetic rats showed a statistically significant decrease in the density of both endothelin receptor subtypes when compared with age-matched control rats. At 90 days, however, the density of endothelin receptors type B was statistically significantly higher than that of control rats, and the innermost layers of the diabetic retina also showed an increase of both endothelin receptor type B receptor and immunoreactive endothelin-1 signal. Insulin treatment during 90 days up-regulated endothelin receptor type A in neural retinal membranes and in the innermost layers of the retina when compared with control retinas.¶Conclusion/interpretation. These results show that the endothelin system is altered in both vascular and neuronal components of the retina in early diabetic retinopathy. The up-regulation of endothelin receptor type A induced by insulin treatment suggests that insulin might be involved in retinal microangiopathy. [Diabetologia (2000) 43: 773–785]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051375
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...