Renin activates the renin-angiotensin system by cleaving
angiotensinogen, produced by the liver, to yield angiotensin I,
which is further converted into angiotensin II by ACE, the
angiotensin-converting enzyme primarily within the capillaries of
the lungs. Angiotensin II then constricts blood vessels, increases
the secretion of ADH and aldosterone, and stimulates the
hypothalamus to activate the thirst reflex, each leading to an
increase in blood pressure.