A simplified method of analysis of cell-conditioned medium for Insulin-like Growth Factor-I (IGF-I) activity

To facilitate further investigation of the relationship between IGF-I and IGF binding proteins (IGFBPs) and their effect on myogenic satellite cells, we developed a procedure for rapid screening of cell-conditioned medium for free IGF-I. This method involves the adaptation and implementation of a DNA vacuum blotting manifold, which allows detection of a broad range of IGF-I and is rather sensitive (detection < 10 ng) when compared to western immunoblots. Additionally, this dot-blot method requires less than 40 minutes prior to the addition of the blotto-antibody mixture. Application of the dot-blot method for analysis of free IGF-I levels in conditioned medium samples offers an alternative to the use of western immunoblots, and may be used in initial screening of large numbers of conditioned medium samples.