Nandrolone-pretreatment enhances cardiac β2-adrenoceptor expression and reverses heart contractile down-regulation in the post-stress period of acute-stressed rats

To investigate whether nandrolone decanoate (ND)-pretreatment can modulate (1) β-adrenoceptor expression and (2) myocardial contractility in response to β-adrenoceptors stimulation with isoproterenol (ISO), in hearts of both normal and stressed rats.Rats were treated with 15 mg/(kg day) of Deca-Durabolin (ND, 1 ml i.m.) or with vehicle (oil) for 14 days. The day after the last injection, the dose–response to ISO (1 × 10−8, 5 × 10−8 and 10−7 M), was studied in isolated rat hearts harvested from unstressed animals (unstressed + vehicle (control) or unstressed + ND) or from stressed animals (stressed + vehicle or stressed + ND): acute stress protocol consisted in restrain for 1 h immediately before sacrifice.ND-pretreatment increased β2-adrenoceptor expression. In baseline conditions all hearts had a similar left ventricular developed pressure (LVDP) and maximum rate of increase of LVDP (dP/dtmax). In hearts of unstressed + vehicle or unstressed + ND, ISO caused a similar increase in LVDP (+90–100%) and dP/dtmax (+120–150%). However, hearts of stressed + vehicle animals showed a marked depression of inotropic response to ISO (i.e. for ISO 1 × 10−8, − 55% in LVDP response versus unstressed). Yet, in hearts of stressed + ND-animals the effect of stress was reversed, showing the highest response to ISO (i.e. for ISO 1 × 10−7, +30% LVDP response versus unstressed).The ND-induced β2-adrenoceptor overexpression does not affect ISO-response in unstressed animals. However, acute stress induces a down-regulation of ISO-response, which is reversed by ND-pretreatment. Since the physiological post-stress down-regulation of adrenergic-response is absent after nandrolone treatment, the heart may be exposed to a sympathetic over-stimulation. This might represent a risk for cardiovascular incidents in anabolic steroid addicts under stressing conditions.