HMOX1 and cyclic hematopoiesis: In MCT-PH and CH-PH rats, simvastatin treatment caused a significant elevation in HO activity from 130 ± 50% of control (M group) to 280 ± 50% of control (MS group, p < 0.05 vs. M group, Figure 6A) and from 150 ± 40% of control (H group) to 280 ± 40% of control (HS group, p < 0.05 vs. H group, Figure 6B).