2014), suggesting that other mechanisms also contributed to the control of the blood pressure in the old females. In another study, we evaluated the role of the renin–angiotensin system, and found that the angiotensin AT1 receptor antagonist, losartan, also reduced the blood pressure in old female SHR, but again the rats remained hypertensive (Yanes et al. 2010), again suggesting the contribution of other systems to mediate the hypertension in the old females. This evidence concerns the gene REN and hypertensive disorder.