Insulin Selectively Downregulates α2-Adrenoceptors in the Arcuate and Dorsomedial Nucleus

Abstract Intracerebroventricular infusion of insulin (2 mU/day) produced selective downregulation of 3 H-paraminoclonidine binding to α 2 -adrenoceptors in the hypothalamic arcuate (14%) and dorsomedial (19%) nuclei out of 16 forebrain areas in Wistar rats. Binding of 3 H-prazosin to α 1 -adrenoceptors was unaffected. This is in keeping with the known effect of insulin on catecholamine and neuropeptide Y metabolism in these brain regions that play an important role in energy homeostasis.