[Effect of growth factor preparations on the proliferation of in vitro cultivated aortic endothelial cells]. / Wirkung von Wachstumsfaktor-Präparationen auf die Proliferation in vitro kultivierter Aorten-Endothelzellen.

A functionally and structurally well-defined calf aortic endothelial cell line has been used to characterize tissue preparations with mitogenic activity by means of cell proliferation kinetics. The following preparations were tested: An extract from corpora lutea (pig), produced by stepwise ammonium sulfate precipitation (CL-S3), a fraction obtained from CL-S3 extract by ion exchange chromatography (CM-S4), and a chorioallantoic membrane preparation (CAM preparation). Under optimal cultivation conditions 100 micrograms CL-S3, 5 micrograms CM-S4, or 100 micrograms CAM preparation per ml medium increased the cell number and growth rate of the endothelial cells in approximately like manner after an incubation period of 48 hours. Compared with CL-S3 these results demonstrate a 20 fold enrichment of the mitogenic activity in the CM-S4 fraction. Under suboptimal cultivation conditions (i.e. a low cell number at the seeding and a reduced nutritive quality) 100 micrograms CL-S3 per ml medium stimulated the cell proliferation up to 12 times at the end of a 6-days-cultivation-period. These results are discussed in connection with the use of these preparations in the angiogenesis research and with respect to the application of selected preparations in cell culture media in order to reduce the serum concentrations.

[The effect of growth factors on cell cultures]. / Die Wirkung von Wachstumsfaktoren auf Zellkulturen.

As sources for cell growth factors with polypeptide nature sera, organs and conditioned culture media can be used. A few samples of such factors are listed in this report. Their main effects on cultured cells consist in the stimulation of DNA-synthesis and proliferation. The knowledge on the mechanism of action of these factors is still incomplete. Some aspects of this question are discussed. The development of chemically defined culture media will be a fundamental prerequisite for further progress in the elucidation of the problems of growth regulation on the cellular level. Certain discrepancies between the effects of the growth factors in vivo and in vitro might arise by the fact that the cells in culture are not provided by adequate substrata when growing on glass or plastic and thus having a cell shape not typical for the in vivo situation. The cell shape may have an influence on the mitogenic response of the cells.