Isolation of the homogeneous constituents from non-diffusible sugar-peptide (NSP) fraction originating from bovine plasma. IV. The influence on cell growth of REF and R-XC cells in vitro.

The effect of the NSP fraction and its four peptide constituents (A, C2, D and G) on the 3H-thymidine incorporation into REF and R-XC cells in vitro was described. Only peptide G (at concentration 5 micrograms/ml) affected the growth of the investigated cells, decreasing the 3H-thymidine uptake to 4-13% relative to untreated control, regardless of the kind of investigated cells. The effect of peptide G, added in concentration 10 ng-1 microgram, however was dependent on the type of investigated cells, suggests that neoplastic transformation changes the response of rat cells in vitro. The possible explanation of the differences in the biological response of the investigated cells to peptide G is proposed.