0
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Rat astroglial somatomedin/insulin-like growth factor binding proteins: characterization and evidence of biologic function

      , ,

      The Journal of Neuroscience

      Society for Neuroscience

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Specific binding proteins (BPs) to somatomedin/insulin-like growth factors (Sm/IGFs) have been identified in conditioned media from a variety of cells in culture. By affinity cross-linking using disuccinimidyl suberate, we have covalently cross-linked radiolabeled somatomedin-C/insulin-like growth factor I (Sm-C/IGF I), insulin-like growth factor II (IGF II) and insulin to BPs in conditioned medium (CM) from cultured astroglial cells derived from cerebral cortices of neonatal rats. Two species of radiolabeled Sm/IGF BP complexes of 40,000 Da (40K) and 45K were identified. Competition with unlabeled Sm- C/IGF I and IGF II demonstrated that the BPs in each complex have similar affinities for Sm-C/IGF I and IGF II. The BP in the 45K complex was about 5-fold more sensitive to competition with unlabeled Sm/IGFs than the BP in the 40K complex, suggesting that it either has a higher affinity for Sm/IGFs or is less abundant. Evidence that the BPs in each complex are distinct includes the following findings: (1) insulin competed with Sm/IGF for binding to the 45K complex, but not the 40K complex, and (2) the BP in the 40K complex, but not the 45K complex, was recognized by antibodies raised against a BP purified from CM of buffalo rat liver (BRL) 3A cells. Growth hormone did not affect the apparent secretion of either BP. The binding activity of both BPs was retained after mild heat treatment, changes to extremes of pH (2–10), and prolonged storage at -20 degrees C, but was destroyed after heating to higher temperatures (80 degrees C and greater), reduction, and proteolytic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

          Related collections

          Author and article information

          Journal
          J Neurosci
          J. Neurosci
          jneuro
          The Journal of Neuroscience
          Society for Neuroscience
          0270-6474
          1529-2401
          1 September 1988
          : 8
          : 9
          : 3135-3143
          Affiliations
          Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill 27514.
          Article
          PMC6569429 PMC6569429 6569429 jneuro;8/9/3135
          10.1523/JNEUROSCI.08-09-03135.1988
          6569429
          3049955
          © 1988 by Society for Neuroscience
          Categories
          Articles
          Custom metadata
          8/9/3135
          3135

          Comments

          Comment on this article