Biochem/physiol Actions L 748337 is a selective, competitive beta 3 adrenergic receptor antagonist, that binds to the receptor with an affinity of 04 nM. The affinities for beta-1 and beta-2 receptors are 154 and 204 nM, respectively. The compound potently inhibits agonist-stimulated lipolysis in adipocytes, as well as agonist induced relaxation of smooth muscle. |