REN and hypertensive disorder: In 1934, Goldblatt et al. [25] developed a model of HTN in dogs by producing renal artery stenosis in one of the two kidneys (2K1C, a renin–angiotensin-system (RAS)-dependent model of HTN) and later, a model in which one kidney was eliminated and a stenosis was produced in the renal artery, resulting in the second model (1K1C; which is a volume-dependent HTN).