Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II type 1 (A
TI) receptor blockers are two separate classes of drugs. Although they are
both effective antihypertensive agents, they exert their effects through di
fferent pharmacological mechanisms. Nonetheless, they have often proved ind
istinguishable in terms of the surrogate endpoints used in short term clini
cal studies. Considerable data are available on the long term benefits of A
CE inhibition; however, studies looking at the long term effects of AT(1) r
eceptor blockade are not yet complete. If ACE inhibitors prove to be distin
guishable from AT1 receptor blockers in terms of disease related outcomes,
the reason may be the selective effects of ACE inhibitors on insulin resist
ance and insulin-mediated vascular function.