EFFECT OF ADRENERGIC RECEPTOR BLOCKADE ON NICOTINIC ACID-INDUCED PLASMA FFA REBOUND

Nicotinic acid administration causes an initial depression in plasma free fatty acids (FFA) followed by a rebound above baseline concentrations. Beta adrenergic blockade with propranolol had no effect on the FFA rebound. Alpha adrenergic blockade with phentolamine completely abolished the FFA rebound and also partially inhibited the initial plasma FFA depression. No relationship between FFA rebound and plasma growth hormone levels was observed. A significant correlation was demonstrated between FFA depression and rebound following nicotinic acid administration. It is proposed that the abolishment of the FFA rebound by alpha adrenergic blockade is related to its inhibition of the initial FFA depression which in turn may be related to antagonistic effects of alpha adrenergic blockers and nicotinic acid on adenyl cyclase activity. © 1969.