Objective To investigate the therapeutic effects of hemin, an inducer of heme oxygenase, in a rat model of gestational hypertension and explore the possible mechanism. Methods Eighteen pregnant SD rats at day 12 of gestation were randomized equally into gestational hypertension model group, hemin treatment group, and normal pregnancy(control)group. In the former two groups, the rats were subjected to daily nitro- L- arginine methyl ester(L- NAME, 80 mg/kg) gavage since gestational day 14 for 7 consecutive d...