Norepinephrine hydrochloride (Levarterenol hydrochloride) is a β1 -selective agonist of the adrenergic receptor with EC 50 of 5.37 μM [1].

Norepinephrine (NE) bitartrate monohydrate predominantly acts as a β1-subtype selective adrenergic agonist, with higher concentrations also engaging the β2-adrenoceptor [1]. In a study utilizing adipocytes derived from the inguinal (iWA) or interscapular (BA) fat pads of neonatal C57BL/6J mice, the impact of AT2 activation on β-adrenergic signaling was investigated by measuring cAMP levels in response to NE (10 μM), both alone and in conjunction with CGP (10 nM). Results showed that NE enhanced cAMP production in iWA as predicted, and this increase was unaffected by CGP. Additionally, NE was observed to promote lipolysis, a process essential for UCP1 protein activation and subsequent heat generation. Furthermore, NE treatment elevated CREB phosphorylation at Ser133, an effect noticeably diminished by CGP co-administration in iWA samples [2].