
TY  - JOUR
A1  - Smythe, GA 
A1  - Bradshaw, JE 
T1  - Different Acute Effects of the Tyrosine Hydroxylase Inhibitors a-Methyl-p-Tyrosine and 3-Iodo-L-Tyrosine on Hypothalamic Noradrenaline Activity and Adrenocorticotrophin Release in the Rat
JF  - Australian Journal of Biological Sciences
JO  - Aust. Jnl. Of Bio. Sci.
Y1  - 1983
VL  - 36
IS  - 6
SP  - 519
EP  - 524
KW  - 
UR  - https://doi.org/10.1071/BI9830519 
N2  - Computerized gas chromatography-mass spectrometry techniques using selected ion monitoring and deuterated internal standards were used to assay simultaneously the medial basal hypothalamic concentrations of dopamine (DA) and noradrenaline (NA) and their major metabolites in individual rats 30 min after the administration of two different inhibitors of tyrosine hydroxylase, a-methyl-ptyrosine (a-MT) and 3-iodo-L-tyrosine (MIT). Consistent with inhibition of DA synthesis, administration of both a-MT and MIT resulted in marked reductions (P<O· 005) in the hypothalamic concentrations of DA and its metabolite homovanillic acid as well as in highly significant increases in prolactin secretion. a-MT administration, but not MIT, resulted in a highly significant decrease in NA concentration and a highly significant increase in the concentration of the NA metabolite 3,4- dihydroxyphenylethyleneglycol (DHPG). The hypothalamic ratio DHPG/NA was thus markedly increased (P<O· 005) by a-MT indicating increased NA neuronal activity. a-MT administration also resulted in increased ACTH secretion (P<O· 0005), an effect not observed following MIT 
ER  -

