REN and hypertensive disorder: In early 1970’s, Laragh classified pathophysiology of essential hypertension into low renin hypertension, and high (or medium) renin hypertension, and suggested that the plasma renin activity levels could be used to predict the BP response to antihypertensive agents.8 For example, volume overloaded sub-type of hypertension associated with a low plasma renin activity may benefit from use of diuretics, whereas pre-dominantly vaso-constrictive type of hypertension, associated with a higher plasma renin levels may benefit from the use of a beta-blocker.