Invertebrate biogenic amine neurotransmitter, related to noradrenalin, that is an adrenoceptor agonist. Stimulates lipolysis in mammalian adipocytes via activation of β3 receptors. Has dual effect on glucose transport in adipocytes: inhibits transport via β3 receptor activation but stimulates transport when oxidized by MAO. Also activates human α2A receptors, inhibiting subsequent cAMP production.