Rat C6 glial cells synthesize insulin-like growth factor I (IGF-I) and express IGF-I receptors and IGF-II/mannose 6-phosphate receptors.
Endocrinology
; 124(4): 1727-36, 1989 Apr.
Article
en En
| MEDLINE
| ID: mdl-2538309
We have used the rat C6 glial cell line as a model system to study the role of insulin-like growth factors (IGF) in neuroglial cells of the central nervous system (CNS). Northern blot analysis of C6 RNA demonstrated the presence of IGF-I mRNA and undetectable IGF-II mRNA. IGF-I and IGF-binding protein(s), but not IGF-II, were detected in C6 glial cell-conditioned medium. The level of IGF-I was 1-4 ng/ml in conditioned medium based on a human IGF-I standard. The immunoreactive IGF-I inhibited [125I]IGF-I binding to the IGF-I receptor on chick embryo fibroblasts and stimulated [3H]thymidine incorporation into chick embryo fibroblast DNA. Competitive binding and affinity cross-linking experiments using [125]IGF-I and [125I]IGF-II demonstrated the presence of IGF-I receptors (type I) and IGF-II/mannose 6-phosphate receptors (type II) on C6 glial cell membranes. An immunoglobulin (no. 3637) directed against the rat IGF-II receptor blocked the degradation of [125I]IGF-II added to C6 glial cells, presumably by blocking receptor-mediated internalization. We were unable to demonstrate an autocrine role for IGF in the C6 glial cell line, since [3H]thymidine incorporation into DNA was stimulated equally well by IGF-I-deficient rat serum and normal serum, and added IGF did not stimulate [3H]thymidine incorporation into DNA when tested alone or when added to IGF-I-deficient serum. We propose that neuroglial cell-derived IGF-I may serve as a paracrine growth stimulus in the central nervous system.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Somatomedinas
/
Factor I del Crecimiento Similar a la Insulina
/
Neuroglía
/
Receptores de Superficie Celular
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Endocrinology
Año:
1989
Tipo del documento:
Article
Pais de publicación:
Estados Unidos