ADRB3 and obesity due to melanocortin 4 receptor deficiency: Antagonistically, plasma catecholamines are important stimulators of lipolysis via adrenergic receptors, particularly through beta-1 (ADRB1) and beta-3 adrenergic receptors (ADRB3) in human WAT [103], and catecholamine-stimulated lipolysis has also been found to be impaired in obesity [104].