Effects of hemin treatment on systolic blood pressure of SHRs and age-matched WKYs.

The mean systolic pressure was calculated from 6 different measurements taken from each animal. (A) Changes in systolic BP in 4- and 8-week-old SHRs (▧) and WKYs (■). BP was higher in 8-week-old SHRs than in age-matched WKYs. (B) Changes in systolic BP in 20-week-old SHRs (▧) and WKYs (■). BP was higher in 20-week-old SHRs than in age-matched WKYs. Hemin treatment lowered BP in 8-week-old SHRs, but not in 4- week-old or 20-week-old SHRs or WKYs at all ages. ZnPP completely abolished the hemin-dependent BP-lowering effect in 8-week-old SHRs. ZnPP significantly increased BP in prehypertensive 4-week-old SHRs (A) but had no effect on BP of adult SHRs (B). Each group contained 10 animals. *P < .01 versus untreated age-matched SHRs. †P < .01 versus age-matched WKYs. Error bars indicate means ± SEM.