An Assay System for the Growth Promoting Activity of Insulin by (3)H-thymidine Incorporation

In a chemically defined serum-free medium, insulin can stimulate DNA synthesis of the mouse mammary tumor-derived cell line GR2H6 up to 3 - 5 fold above the control group as measured by (3)H-thymidine incorporation. By growing GR2H6 cells in the 24-well and 96-well plates, a bioassay system for the growth promoting activity of insulin has been established. This method has the advantages such as easy operation, less time-consuming and suitable for measuring a large number of samples simultaneously. It may provide a novel model system for studies on the relationships between the growth promoting activity and the structure of insulin.