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Signs of hyperestrogenism may include heightened levels of one or more of the estrogen sex hormones (usually estradiol and/or estrone), lowered levels of follicle-stimulating hormone and/or luteinizing hormone (due to suppression of the hypothalamic–pituitary–gonadal axis by estrogen), and lowered levels of androgens such as testosterone (generally only relevant to males). [1]
Estradiol (E2), also called oestrogen, oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of female reproductive cycles such as estrous and menstrual cycles .
Aromatase excess syndrome (AES or AEXS) is a rarely diagnosed genetic and endocrine syndrome which is characterized by an overexpression of aromatase, the enzyme responsible for the biosynthesis of the estrogen sex hormones from the androgens, in turn resulting in excessive levels of circulating estrogens and, accordingly, symptoms of hyperestrogenism.
The four major naturally occurring estrogens in women are estrone (E1), estradiol (E2), estriol (E3), and estetrol (E4). Estradiol (E2) is the predominant estrogen during reproductive years both in terms of absolute serum levels as well as in terms of estrogenic activity.
Average number of moderate-to-severe hot flashes per week with placebo and different doses of oral estradiol in menopausal women [40] [41]. Estradiol is used in menopausal hormone therapy to prevent and treat moderate to severe menopausal symptoms such as hot flashes, vaginal dryness and atrophy, and osteoporosis (bone loss). [11]
Testosterone and estradiol circulate in the bloodstream, loosely bound mostly to serum albumin (~54%), and to a lesser extent bound tightly to SHBG (~44%). Only a very small fraction of about 1 to 2% is unbound, or "free," and thus biologically active and able to enter a cell and activate its receptor.
Estradiol is an estrogen, or an agonist of the nuclear estrogen receptors (ERs), the estrogen receptor alpha (ERα) and the estrogen receptor beta (ERβ). [1] [2] [6] In one study, the EC 50 Tooltip half-maximal effective concentration value of estradiol for the human ERα was 50 pM (0.05 nM) and for the human ERβ was 200 pM (0.2 nM).
There is high interindividual variability in the levels of estradiol achieved with oral estradiol, which is likely related to the high first-pass effect. [12] This variation has been reported to be in the range of 28 to 127%, or about 4.6-fold maximal difference in levels between individuals, in terms of mean area-under-the-curve levels of ...