Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1988-11-18
pubmed:abstractText
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)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:volume
8
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3135-43
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Rat astroglial somatomedin/insulin-like growth factor binding proteins: characterization and evidence of biologic function.
pubmed:affiliation
Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill 27514.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't