Effect of serum on DNA synthesis in vascular SMCs.

Cells were treated with serum (10%) for 24 hours in the presence or absence of ZnPP (20 μM), SnPP (20 μM), Hb (50 μM), or desferrioxamine (100 μM). The heme oxygenase inhibitors and desferrioxamine were added simultaneously with serum, whereas Hb was given 12 hours after serum addition. Results are means ± SEM of 4 separate experiments. *Statistically significant effect of serum.⁺Statistically significant effect of HO inhibitors and Hb.