Beta-adrenoceptors are involved in the induction of myocardial hypertrophy in the post ischemic heart. Pre- and post-conditioning succeeds in significant reduction of infarct sizes. It is unknown if the response of this receptor is modified in post-ischemic myocardium. This study investigates the pro-hypertrophic effects of beta-adrenoceptors in regard to ischemic pre- and post- conditioning. Isolated, perfused hearts (n=64, normotensive wistar rats) were subjected to 45 min no-flow ischemia - 120 min reperfusion and divided into eight groups: normoxie (Nx), ischemia (Isch), pre-conditioning (IPC), post-conditioning (IPoC), Nx+ISO, Isch+ISO, IPC+ISO and IPoC+ISO (ISO=Isoprenalin, 10 nM, application 30 min after reperfusion for 10 min). Myocardial function was evaluated by continuous assessment of LVDP, the expression of pro-hypertrophic genes (ANF, ODC), anti-apoptotic genes (bcl-2, bcl-xl) and pro-apototic genes (bax) was detected by real time RT-PCR. There were no differences in the recovery of LVDP between Isch, IPC and IPoC. ISO caused an induction of ODC expression (Nx: 419%, Isch: 225%, IPC: 341%) except in the IPoC group. The expression of ANF caused by ISO was much higher in post-ischemic myocard compared to normoxie. Postconditioning inhibits the beta-adrenoceptor induced expression of ODC and bcl-2, reduces the expression of ANF (219%) and normalized the expression of bcl-xl.