Insulin-like growth factor I/somatomedin-C (IGF-I/SM-C) and glucocorticoids synergistically regulate mitosis in competent human fibroblasts.
J Cell Physiol
; 116(2): 191-7, 1983 Aug.
Article
em En
| MEDLINE
| ID: mdl-6306016
ABSTRACT
In serum-free medium, insulin-like growth factor-I/somatomedin-C (IGF-I/SM-C) was weakly mitogenic for adult human fibroblasts in culture. However, in the presence of 0.5% human hypopituitary serum (HHS), which by itself had little effect, there was a marked dose-dependent response to IGF-I/SM-C with a 10- to 20-fold increase in [3H]thymidine incorporation at 25 ng/ml IFG-I/SM-C. With the further addition of dexamethasone or hydrocortisone to the combination of IGF-I/SM-C + 0.5% HHS, there was a dramatic synergistic effect resulting in a 60- to 70-fold increase in [3H]thymidine incorporation. This stimulation was two times greater than that seen with 20% FCS. In contrast, glucocorticoids had no effect in serum-free medium or with HHS alone. These [3H]thymidine incorporation results were clearly supported by cell replication studies. Dose-response curves for 125I IGF-I/SM-C binding and IGF-I/SM-C stimulation of [3H]thymidine incorporation were similar with 1/2 maximal effects for both at 5 ng/ml. However, the striking synergism seen with glucocorticoids occurred in the absence of any glucocorticoid-induced change in IGF-I/SM-C binding, indicating that the interaction of IGF-I/SM-C and glucocorticoids occurs at a postreceptor level. These data demonstrate that in the presence of a low concentration of HHS, IGF-I/SM-C and glucocorticoids stimulate complete cell cycle traverse and replication of human fibroblasts.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Somatomedinas
/
Glucocorticoides
/
Insulina
/
Mitose
Limite:
Adult
/
Humans
/
Male
Idioma:
En
Revista:
J Cell Physiol
Ano de publicação:
1983
Tipo de documento:
Article