Aromatase activity in brain and pituitary of immature and mature Atlantic salmon (Salmo salar L.) parr.

Brain homogenates from Atlantic salmon parr converted tritiated androstenedione to testosterone, estrone, and 17 beta-estradiol. The formation of estrogens was markedly higher in homogenates of whole brains from mature parr males than from immature parr males. The highest estrogen synthesis was found in the telencephalon and diencephalon. In both of these parts the estrogen production was higher in mature males than in immature males. There was no difference in estrogen formation by pituitaries from immature female and immature male parr, whereas the formation of estrogens and testosterone was higher in the mature male parr.