Subject(s)
Growth Hormone/metabolism , Peptide Hydrolases/metabolism , Somatomedins/biosynthesis , Trypsin/metabolism , Animals , Cartilage/metabolism , Cattle , Cyanogen Bromide/metabolism , Growth Hormone/isolation & purification , Hirudins/pharmacology , Humans , Molecular Weight , Phenylmethylsulfonyl Fluoride/pharmacology , Pituitary Gland/analysis , Protease Inhibitors , Rats , Somatomedins/antagonists & inhibitors , Swine , Temperature , Thrombin/antagonists & inhibitorsABSTRACT
Baby hamster kidney cells (BHK) were able to proliferate in the complete absence of serum in synthetic medium supplemented with insulin, transferrin, fibroblast growth factor and epidermal growth factor on cell culture dishes coated with fibronectin. Although the addition of individual supplements had little or no effect on cell growth, the combination of the supplements resulted in a significant synergistic effect. The defined medium was also capable of supporting the clonal growth of BHK cells in the absence of serum. Studies on the effect of hormonal supplementation in the presence of low concentrations of fetal calf serum suggest that the function of serum is to supply hormones and growth factors for cell growth.
Subject(s)
Cells, Cultured/cytology , Growth Substances/pharmacology , Hormones/pharmacology , Animals , Cell Division/drug effects , Cell Line , Cricetinae , Culture Media , Drug Synergism , Epidermal Growth Factor/pharmacology , Fibronectins/pharmacology , Insulin/pharmacology , Kidney/cytology , Transferrin/pharmacologyABSTRACT
Extracts of bovine hypothalamus were found to contain a significant level of mitogenic activity when tested in a Swiss 3T3 cell [3H]dThd incorporation assay and in a human umbilical vein endothelial cell growth assay. The mitogenic activity responsible for 3T3 cell activity was purified and characterized as a fibroblast growth factor (FGF)-like mitogen. Neither the biologically active FGF-like mitogen purified from the hypothalamus extracts nor FGF purified from bovine pituitary glands was mitogenic when added to human endothelial cells in vitro, suggesting the presence of more than one mitogen in the hypothalamic extracts. The 3T3 and endothelial cell biological activities of hypothalamic extracts were both found to be inactivated by trypsin, subtilisin, and heat treatment, but were stable to dialysis. The endothelial cell growth factor activity could be efficiently separated from the FGF activity by gel exclusion chromatography. The endothelial cell mitogen possessed a molecular weight of approximately 75,000, whereas that of FGF was approximately 15,000. The endothelial cell growth factor activity was found to be inactivated with reducing agents whereas the 3T3 cell mitogenic activity was stable after incubation with 2-mercaptoethanol. Significant levels of endothelial cell mitogenic activity were also found in extracts of bovine brain and pituitary glands.
