Effects of adrenaline infusion on plasma lipids and noradrenaline levels in rabbits with adriamycin-induced cardiomyopathy

1. We investigated the acute effects of adrenaline infusion on plasma lipid levels in vehicle- and adriamycin-treated rabbits. Lipids were measured before and 30 and 60 min after the commencement of continuous intravenous administration of adrenaline (0.06 μg/kg per min) or saline in pentobarbital-anaesthetized rabbits. 2. Adrenaline infusion significantly increased plasma free fatty acid (P < 0.05) and noradrenaline (NA) levels (P < 0.05) in vehicle-treated control rabbits, but not in adriamycin-treated rabbits. However, adrenaline had no effect on plasma total cholesterol, free cholesterol, high-density lipoprotein-cholesterol, triglyceride or phospholipid levels. 3. Pretreatment with propranolol almost completely inhibited increased plasma free fatty acid and NA levels associated with adrenaline infusion, suggesting that adrenaline increases plasma free fatty acid and NA levels via the stimulation of β-adrenoceptors in vehicle-treated rabbits. 4. It is suggested that both the production of plasma free fatty acids and the release of NA via the activation of β-adrenoceptors is reduced in rabbits with adriamycin-induced cardiomyopathy. This may be related to the down-regulation of β-adrenoceptors caused by elevated plasma NA levels induced by cardiac failure.