Growth Promoting Activity of Chimeric Molecules of "Insulin-Insulin-like Growth Factor-I"

The chimeric molecules of "Insulin-Insulin-like Growth Factor-I", Ins/IGFI(8) and Ins/IGF-I(11) were obtained by means of enzymatic semisynthesis. The growth promoting activity of these chimeric molecules were evaluated with a mouse mammary tumor derived cell line, GR2H6, and compared with that of IGF-I, insulin and desoctapeptide insulin (DOI). Both compounds have lower activities than IGF-I and effects similar to insulin, but are more potent mitogens than DOI. These results indicate that the C-terminus of insulin B-chain is importantly involved in its growth promoting activities.