The best stimulant for all mammalian cell is fetal calf serum or bovine serum. If wish to have further induction with a particular mitogen, choose a cell specific mitogen. Hope this answers

Thanks so much Kumaravelu.

Regards,

I would like to add that one can increase the percentage of serum in the medium up to 20%. Some cell lines of epithelial and mesenchymal  origin tend to do better at this higher serum levels. Further, one can add other growth factors such as FGF and PDGF. 

Thanks so much Prof. Divaker