Oestrogen metabolism in adult rat's brain

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Abstract
In vitro incubation of pituitary, hypothalamus and cerebral cortex with [3H]estrogens revealed that the estrogens are actively metabolized by these tissues. The covalent binding of estrone and estradiol to acid precipitable proteins was observed. Pituitary from male rats exhibited higher covalent binding of estrogens than females. The 2-hydroxylation was greater than 16-hydroxylation. Male pituitary exhibited higher 2-hydroxylation of estrogens than females. No such sexual dimorphism was observed in 16-hydroxylation. C17-reduction was greater than oxidation in these tissues. The C17-reduction in pituitary and hypothalamus from females was greater than males, which is in contradistinction to protein binding and 2-hydroxylation of estrogens. In both male and female animals, the pituitary was metabolically more active than hypothalamus and cortex. In addition, estradiol was hydroxylated more than estrone either at 2- or 16-positions. In the CNS and pituitary, the estrogens are evidently metabolized preferentially by 2-hydroxylation pathway and the in situ metabolism of estrogens in neuroendocrine tissues may be important in the control of estrogen effects on neuroendocrine function and sex behavior.