Adipocytes as a new source of catecholamine production

► Brown and white adipose tissue of rat express catecholamine biosynthetic enzymes. ► Isolated adipocytes produce little amount of norepinephrine and epinephrine. ► Sympathoadrenal system is not the only source of catecholamines in adipose tissue. Catecholamines are an important regulator of lipolysis in adipose tissue. Here we show that rat adipocytes, isolated from mesenteric adipose tissue, express genes of catecholamine biosynthetic enzymes and produce catecholamines de novo. Administration of tyrosine hydroxylase inhibitor, alpha-methyl-p-tyrosine, in vitro significantly reduced concentration of catecholamines in isolated adipocytes. We hypothesize that the sympathetic innervation of adipose tissues is not the only source of catecholamines, since adipocytes also have the capacity to produce both norepinephrine and epinephrine.