Angiotensin II has a number of individual effects which tend to act to restore plasma volume and blood pressure.
Central nervous system:
- stimulation of circulatory centre with resulting increase in sympathetic outflow and vasoconstriction
- stimulation of hypothalamus to:
- lower threshold for release of ADH
- increase thirst
- increase desire for salt
Cardiovascular system:
- extremely potent vasoconstrictor, particularly of efferent capillaries
- minimal effect on normal blood pressure homeostasis, but may have a role in maintaining the glomerular filtration rate - see below
Renal:
- stimulates sodium reabsorption in proximal convoluted tubule
- possible local feedback loop whereby an increasing salt concentration through the proximal convoluted tubule would lead to increased circulating angiotensin II. Angiotensin II constricts the afferent arteriole to cause a decreased glomerular filtration rate.
- raises threshold for renin secretion into afferent arterioles - negative feedback
Adrenal cortex:
- stimulates aldosterone secretion
These peripheral effects of angiotensin II may be minimized by angiotensin receptor antagonists such as losartan.