Role of Phospholipid in Adrenaline-Induced Lipolysis and Cyclic AMP Production

Abstract

Lipid micelles consisting of a glyceride mixture (triolein, diolein, and monoolein) and lecithin bound adrenaline-¹⁴C more strongly than did micelles consisting of the glyceride mixture only. Lipid micelles consisting of the glyceride mixture and phosphatidic acid also bound adrenaline-¹⁴C effectivily, whereas lipid micelles consisting of the glyceride mixture and diglyceride, obtained from lecithin, did not bind the hormone strongly. Both phenoxybenzamine (an αblocker) and propranolol (a β-blocker) strongly inhibited the association between adrenaline-¹⁴C and lipid micelles consisting of the glyceride mixture and lecithin. Propranolol, inhibited adrenaline-induced lipolysis in both fat cells and fat globules, whereas, phenoxybenzamine, did not affect adrenaline-induced lipolysis. Both agents reduced adrenaline-induced adenylcyclase activation in fat cell ghosts. Phospholipid was also found to be related with adrenaline-mediated adenylcyclase activation.