Answer:
granular cells of the juxtaglomerular apparatus
Step-by-step explanation:
Renin or angiotensinogenase is a circulating enzyme released by granular cells of the juxtaglomerular apparatus of the kidney in response to a series of physiological stimuli and causes activation of the renin-angiotensin-aldosterone system.
Renin transforms angiotensinogen from the liver into angiotensin I, which is transformed into angiotensin II by the lungs.