ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Human neonatal skin fibroblasts plated sparsely in MCDB 105 traversed a complete cell cycle in the absense of serum or serum-derived proteins. Addition of pure PDGF did not significantly increase entrance into S phase as revealed by 3H-thymidine labeling index or clonal growth on palladium islands. In subphysiologic Ca2+ concentrations or in the presence of a calmodulin inhibitor, W7, proliferation in the absence of growth factors ceased and PDGF became mitogenic. In contrast, confluent fibroblast cultures were stimulated by PDGF in physiologic Ca2+ concentrations. This was also the case with sparse adult skin fibroblast cultures while a fetal strain entered S in the absence of PDGF even in low extracellular Ca2+ concentrations. EGF gave similar results as PDGF in all experiments performed. This proposes a similar role for the two growth factors in the cell cycle. However, a difference in the mechanisms of action of PDGF and EGF is indicated by the fact that PDGF and EGF were additive at optimal concentrations when maximal growth response by a single growth factor was restricted by a subphysiologic extracellular Ca2+ concentration.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041180213
