Increased α2‐ but similar β‐adrenergic receptor activities in subcutaneous gluteal adipocytes from females compared with males

Abstract. α 2 and β ‐adrenergic binding and action were studied in subcutaneous adipocytes from the gluteal region in females and males. The β ‐selective antagonist 3 Hdihydroalprenolol and the α 2 ‐selective antagonist 3 Hyohimbine were used to identify the β ‐ and the α 2 ‐receptor, respectively. The biological effects mediated by these receptors were determined by measuring the glycerol release induced by isoproterenol ( β ‐receptor agonist) and by clonidine ( α 2 ‐receptor agonist). The study consisted of health volunteers (eighteen females and fifteen males). Compared to men the α 2 ‐receptor binding was increased by 73% ( P 0·05). This increased α 2 ‐receptor binding in female and adipocytes was associated with a significantly increased sensitivity ( P 1 μ mol l ‐1 ). However, at low concentrations of adrenaline the lipolytic effect was significantly reduced in female gluteal adipocytes ( P < 0·05), whereas the inhibitory effect was similar between females and males. It is concluded that female gluteal adipocytes possessed more α 2 ‐adrenergic receptors than male adipocytes. This increased binding was accompanied by enhanced antilipolytic effect of clonidine and reduced lipolytic effect of low concentrations of adrenaline. Thus, it is suggested that the increased α 2 ‐receptors in female gluteal adipocytes might be related to the enhanced tendency for females to accumlate fat in this region.