Norepinephrine hydrochloride (Levarterenol hydrochloride; L-Noradrenaline hydrochloride) is a β₁-selective adrenergic receptor agonist with EC₅₀ of 5.37 μM. IC50 & Target: EC50: 5.37 μM (β₁-selective adrenergic receptor)^[1] In Vitro: Norepinephrine (NE) bitartrate monohydrate is generally considered to be a β₁-subtype selective adrenergic agonist. Norepinephrine(NE) also has direct activity at the β₂-adrenoceptor in higher concentrations^[1]. Adipocytes from the inguinal fat pad (iWA) or the interscapular fat pad (BA) are isolated from neonatal wild-type C57BL/6J mice and cultured. To examine the effect of activating AT2 upon β-adrenergic signaling, cAMP production is first assessed in response to Norepinephrine (NE, 10 µM) with or without CGP (10 nM) co-treatment. Norepinephrine (NE) increases cAMP as expected in iWA, and CGP does not alter this effect. Norepinephrine (NE) is also known to induce lipolysis, and liberated fatty acids are required to functionally activate UCP1 protein and to stimulate heat production. CREB phosphorylation at Ser133 is increased after Norepinephrine (NE) treatment and significantly attenuated with CGP co-treatment in mouse iWA^[2].