Why is the growth rate of HDMEC reduced when hydrocortisone is removed from Endothelial Cell Growth Medium MV (C-22120)?

Epidermal Growth Factor (EGF) and hydrocortisone are known to have a synergistic effect on the proliferation of human dermal microvascular endothelial cells (HDMEC).
When hydrocortisone is removed from the Endothelial Cell Growth Medium MV Kit (C‑22120), this synergistic interaction is lost. As a consequence, cell proliferation is clearly reduced, even though EGF is still present.
 
Conclusion
For optimal growth and proliferation of HDMEC, hydrocortisone should be included as specified in the complete Endothelial Cell Growth Medium MV formulation.