ISSN:
0021-9541
Schlagwort(e):
Life and Medical Sciences
;
Cell & Developmental Biology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Biologie
,
Medizin
Notizen:
We investigated the influence of transforming growth factor-β (TGF-β) on DNA synthesis in human fetal fibroblasts, as measured by the incorporation of [3H] thymidine and cell replication. In serum-free medium, without additional peptide growth factors, TGF-β had no action on thymidine incorporation. However, in the presence of 0.1% v/v fetal calf serum, TGF-β exhibited a bi-functional action on the cells. A dose-dependent stimulation of [3H] thymidine incorporation, and an increase in cell number, occurred with fibroblasts established from fetuses under 50 g body weight, with a maximum stimulation seen at 1.25 ng/ml. For fibroblasts from fetuses of 100 g or greater body weight, TGF-β caused a dose-related decrease in thymidine uptake with a maximal inhibition at 2.5 ng/ml, and a small decrease in cell number. When DNA synthesis was stimulated by the addition of somatomedin-C/insulin-like growth factor I, epidermal growth factor, or platelet-derived growth factor, their actions were potentiated by the presence of TGF-β on cells derived from fetuses under 50 g body weight, but inhibited on cells obtained from the larger fetuses wieghing more than 100 g. Similar results were found for changes in cell number in response to TGF-β when stimulated by SM-C/IGF I. The ability of TGF-β to modulate [3H] thymidine incorporation did not involve a change in the time required for growth-restricted cells to enter the S phase of the replication cycle. These data suggest that TGF-β may exert either a growth-promoting or growth-inhibiting action on human fetal connective tissues in the presence of other peptide growth factors, which is dependent on fetal age and development.
Zusätzliches Material:
8 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jcp.1041280226
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