Xenoestrogen
Xenoestrogens are clinically significant because they can mimic the effects of endogenous estrogen and thus have been implicated in precocious puberty and other disorders of the reproductive system.
High-dose estrogen
Estrogens are agonists of the estrogen receptors (ERs), the biological target of endogenous estrogens such as estradiol. When used in high doses, estrogens are powerful antigonadotropins, strongly inhibiting secretion of the gonadotropins luteinizing hormone and follicle-stimulating hormone from the pituitary gland, and in men are able to completely suppress gonadal androgen production and reduce testosterone levels into the castrate range. This is most of the basis of their use in prostate cancer and benign prostatic hyperplasia. When estradiol or an estradiol ester is used for HDE in men, levels of estradiol of at least approximately 200 pg/mL are necessary to suppress testosterone levels into the castrate range.