Effect of growth factors on the differentiation of chick precardiac mesoderm in vitro.

We have found that precardiac mesoderm extirpated from chicken blastoderm at stage 5 fails to differentiate into beating tissue when cultured in Eagle's minimum essential medium (MEM), while it can pulsate provided either the endoderm is present or serum is added to the MEM. To identify the factor(s) which influence early myocardial differentiation, we examined the effect of insulin-like growth factor 1 (IGF-1), activin A and basic fibroblast growth factor (bFGF). All these growth factors showed a stimulating effect on myocardial differentiation and it is conceivable that these factors exhibit the same effect in vivo.