The following diagram shows the renin-angiotensin-aldosteron system (RAAS) which plays an important role in the 
regulation of fluid and electrolyte balance (sodium and volume homeostasis).
Renin is an enzyme that cleaves angiotensinogen to form angiotensin I. It is converted to angiotensin II by the angiotensin-converting enzyme (ACE). Angiotensin II stimulates the synthesis and release of aldosteron, this aldosteron hormone increase the absorption of sodium and excretion of potassium in the distal tubules and collecting ducts of nephrons in the kidney.
Find section about Angiotensin-converting enzyme inhibitor (ACEI) for the treatment of hypertension, list of ACEIs, medical conditions related such Heart failure, Previous myocardial infarction, Coronary heart disease, and Diabetes, Adverse effects of angiotensin-converting enzyme inhibitors in this physician guideline of pdf filetype (source: hkmj.org).
