Histamine lipolytic activity and semicarbazide-sensitive amine oxidase (SSAO) of rat white adipose tissue (WAT)

Histamine has previously been described as a possible substrate for the semicarbazide-sensitive amine oxidase activity (SSAO) of rat white adipose tissue (WAT). We report here on a histamine function in this tissue which concerns the activity of this deaminating system distinct from the classical diamine oxidase. Our results show that: (1) histamine plays a role in controlling rat adipose tissue lipolysis with the contribution of H1 and H2 receptors that participate in histamine lipolysis in an opposite way. Both H1 and H2 roles can be differentiated using selective agonists (2- and 4-methyl histamine) and antagonists (pyrilamine and cimetidine); (2) histamine might also control rat lipolysis induced by noradrenergic agonists; (3) the SSAO present in rat WAT controls histamine levels at the receptor sites as shown by the modification of histamine lipolytic potency obtained when inhibitors of this enzyme are used.