This is a great PDF study, for instance, phytoestrogens reduce aromatase, and only unbound estrogens can enter target-tissue cells and induce biological activity. Highlighted text are key points of interest.
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In women, estrogens are synthesized from cholesterol in the ovaries in response to pituitary hormones. In an adult woman with normal cycles, the ovarian follicle secretes 70 to 500 μg of estradiol per day, depending on the phase of the menstrual cycle. Estradiol can be converted to estrone and vice versa, and both can be converted to estriol, the major urinary metabolite. Estrogens are also produced by the aromatization of androgens in fat cells, skin, bone, and other tissues.
After menopause, most endogenous estrogen is produced in the peripheral tissues by the conversion of androstenedione, which is secreted by the adrenal cortex, to estrone. In addition, some estrogen continues to be manufactured by aromatase in body fat, and the ovaries continue to produce small amounts of the male hormone testosterone, which is converted to estradiol. The total estrogen produced after menopause, however, is far less than that produced during a woman’s reproductive years.
Nutritional Influences on Estrogen Metabolism
http://www.afmcp-sa.com/ansr/MET451%20Endocrine%20ANSR.pdf
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In women, estrogens are synthesized from cholesterol in the ovaries in response to pituitary hormones. In an adult woman with normal cycles, the ovarian follicle secretes 70 to 500 μg of estradiol per day, depending on the phase of the menstrual cycle. Estradiol can be converted to estrone and vice versa, and both can be converted to estriol, the major urinary metabolite. Estrogens are also produced by the aromatization of androgens in fat cells, skin, bone, and other tissues.
After menopause, most endogenous estrogen is produced in the peripheral tissues by the conversion of androstenedione, which is secreted by the adrenal cortex, to estrone. In addition, some estrogen continues to be manufactured by aromatase in body fat, and the ovaries continue to produce small amounts of the male hormone testosterone, which is converted to estradiol. The total estrogen produced after menopause, however, is far less than that produced during a woman’s reproductive years.
Nutritional Influences on Estrogen Metabolism
http://www.afmcp-sa.com/ansr/MET451%20Endocrine%20ANSR.pdf
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