Renin plays impoant role in

Stimulation of the renin-angiotensin-aldosterone system leads to vasoconstriction, salt and water retention, sympathetic nervous system activation. This is mediated by angiotensin II, a potent constrictor of aerioles in both the kidney and the systemic circulation . Activation of the sympathetic nervous system may initially maintain cardiac output through an increase in myocardial contractility, hea rate and peripheral vasoconstriction. However, prolonged sympathetic stimulation leads to cardiac myocyte apoptosis, hyperophy and focal myocardial necrosis.renin also has an essential role in renovascular hypeension.Renovascular hypeension is another renin-mediated form of hypeension. Obstruction of the renal aery leads to decreased renal perfusion pressure, thereby stimulating renin secretion. Over time, as a consequence of secondary renal damage, this form of hypeension may become less renin dependent. ref:Harrison&;s principles of internal medicine,ed 18,pg no 2044