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 m easured before and 30 and 60 min after the commencement of continuous intravenous administration of adrenaline (0.06 mu g/kg per min) or sal ine in pentobarbital-anaesthetized rabbits. 2. Adrenaline infusion sig nificantly increased plasma free fatty acid (P < 0.05) and noradrenali ne (NA) levels (P < 0.05) in vehicle-treated control rabbits, but not in adriamycin-treated rabbits. However, adrenaline had no effect on pl asma total cholesterol, free cholesterol, high-density lipoprotein-cho lesterol, triglyceride or phospholipid levels. 3. Pretreatment with pr opranolol almost completely inhibited increased plasma free fatty acid and NA levels associated with adrenaline infusion, suggesting that ad renaline increases plasma free fatty acid and NA levels via the stimul ation of beta-adrenoceptors in vehicle-treated rabbits. 4. It is sugge sted that both the production of plasma free fatty acids and the relea se of NA via the activation of beta-adrenoceptors is reduced in rabbit s with adriamycin-induced cardiomyopathy. This may be related to the d own-regulation of beta-adrenoceptors caused by elevated plasma NA leve ls induced by cardiac failure.