The circulating Ang II levels in PT-Agtr1a−/− mice remained at about one-third of those in WT mice, suggesting that the expression of renin mRNAs in the kidney was not activated, and active renin was not released from the kidney into the circulation in PT-Agtr1a−/− mice during the development of 2K1C hypertension. This evidence concerns the gene REN and Hypertension.