Effect of oestradiol-17 beta on the metabolism of noradrenaline in brain slices of ovariectomized rats
Köster, G.; Breuer, H.
Acta Endocrinologica 98(1): 1-7
1981
ISSN/ISBN: 0001-5598 PMID: 7282262 Document Number: 173048
Ovariectomized rats received a single injection of 10 .mu.g estradiol-17.beta. 3-benzoate; 90 min or 19 h after injection, slices of various brain areas were prepared and incubated with [3H]noradrenaline [norepinephrine, NE] for 30 min. Methylated and non-methylated metabolites of [3H]NE were determined after chromatographic separation. At 19 h after administration of estradiol-17.beta. 3-benzoate, the formation of normetanephrine, 3-methoxy-4-hydroxyphenylglycol and 3-methoxy-4-hydroxy mandelic acid was decreased (P < 0.05) in hypothalamic tissue; that of 3,4-dihydroxy mandelic acid was increased (P < 0.001). In thalamus tissue a decrease of normetanephrine (P < 0.01) was also observed. No conclusive results were obtained with hypophyseal tissue. Estrogens apparently reduce the methylation of NE, probably through a competitive inhibition of the catechol-O-methyl-transferase by 2-hydroxylated estrogens.