TY - JOUR T1 - Increased Synthesis of Catecholamines in the Intact Rat following Administration of α-Adrenergic Blocking Agents JF - Molecular Pharmacology JO - Mol Pharmacol SP - 457 LP - 464 VL - 4 IS - 5 AU - WALLACE DAIRMAN AU - ROBERT GORDON AU - SYDNEY SPECTOR AU - ALBERT SJOERDSMA AU - SIDNEY UDENFRIEND Y1 - 1968/09/01 UR - http://molpharm.aspetjournals.org/content/4/5/457.abstract N2 - The present study was undertaken to evaluate the effects of α-blocking agents on the rate of catecholamine synthesis in vivo. It was found that phentolamine and phenoxybenzamine increase the formation of radioactive norepinephrine and epinephrine in rat tissues when L-tyrosine-14C is used as a precursor but not when L-dopa-3H is the precursor. These findings indicate that α-blocking agents increase catecholamine synthesis by stimulating tyrosine hydroxylase activity. ER -