T
he peroxisome proliferator activated receptors PPAR
hars/alp
ha.gif" BORDER=0>, PPAR
hars/gamma.gif" BORDER=0 >, and PPAR
hars/delta.gif" BORDER=0 > are ligand-activated transcriptionfactors t
hat play a key role in lipid
homeostasis. T
he fibrates raise circulating levels of
hig
h-density lipoproteinc
holesterol and lower levels of triglycerides in part t
hroug
h t
heir activity as PPAR
hars/alp
ha.gif" BORDER=0> agonists;
however, t
helow potency and restricted selectivity of t
he fibrates may limit t
heir efficacy, and it would be desirable todevelop more potent and selective PPAR
hars/alp
ha.gif" BORDER=0> agonists. Modification of t
he selective PPAR
hars/delta.gif" BORDER=0 > agonist
1(GW501516) so as to incorporate t
he 2-aryl-2-met
hylpropionic acid group of t
he fibrates led to a markeds
hift in potency and selectivity toward PPAR
hars/alp
ha.gif" BORDER=0> agonism. Optimization of t
he series gave
25a, w
hic
h s
howsEC
50 = 4 nM on PPAR
hars/alp
ha.gif" BORDER=0> and at least 500-fold selectivity versus PPAR
hars/delta.gif" BORDER=0 > and PPAR
hars/gamma.gif" BORDER=0 >. Compound
25a(GW590735)
has been progressed to clinical trials for t
he treatment of diseases of lipid imbalance.