Effect of catecholamines and β-blockers on linoleic acid desaturation activity.

The effect of catecholamines and adrenergic blocking agents on the oxidative desaturation of linoleic acid in rat liver microsomes was studied. Epinephrine (1 mg/kg/body weight) produced a significant decrease on the conversion of [1-(14)C]linoleic acid to γ-linolenic acid. The effect of epinephrine was blocked by single injections of the β blockers propranolol (10 mg/kg body weight) or dichloroisoproterenol 30 min before the hormone treatment. Isoproterenol (100 μg/kg body weight) produced a significant decrease on the activity of the linoleyl-CoA desaturase. The effect of the catecholamines was postulated to be mediated through β receptors by an enhancement of the intracellular levels of cyclic AMP.