Inhibition of the in vivo biosynthesis and changes of catecholamine levels in rat brain after α-methyl-p-tyrosine; time- and dose-response relationships

Male Sprague-Dawley rats were given 0.407 mmoles/kg of D,l-α-methyl-p-tyrosine methylester HCl (H44/68; α-MT) at eleven time-points between 0–24h, or 8 doses between 0.013–1.628 mmoles/kg of the drug at 1 h before i. v. injection of 160 μCi tyrosine-2,6-3H. The rats were killed 15 min after tyrosine-3H and brain α-MT, tyrosine and catecholamines (endogenous and labelled), and plasma α-MT and tyrosine (-3H) were chromatographically isolated before being assayed spectrophotofluorimetrically (endogenous) or by liquid scintillation methods (labelled compounds).