Xenoestrogen
Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens. Because the primary route of exposure to these compounds is by consumption of phytoestrogenic plants, they are sometimes called "dietary estrogens". Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins.
Gonadotropin-releasing hormone agonist
A gonadotropin-releasing hormone agonist (GnRH agonist) is a type of medication which affects gonadotropins and sex hormones. They are used for a variety of indications including in fertility medicine and to lower sex hormone levels in the treatment of hormone-sensitive cancers such as prostate cancer and breast cancer, certain gynecological disorders like heavy periods and endometriosis, high testosterone levels in women, early puberty in children, as a part of transgender hormone therapy, and to delay puberty in transgender youth among other uses. GnRH agonists are given by injections into fat, as implants placed into fat, and as nasal sprays.
Side effects of GnRH agonists are related to sex hormone deficiency and include symptoms of low testosterone levels and low estrogen levels such as hot flashes, sexual dysfunction, vaginal atrophy, osteoporosis, infertility, and diminished sex-specific physical characteristics. They are agonists of the GnRH receptor and work by increasing or decreasing the release of gonadotropins and the production of sex hormones by the gonads. When used to suppress gonadotropin release, GnRH agonists can lower sex hormone levels by 95% in both sexes.
GnRH was discovered in 1971, and GnRH analogues were introduced for medical use in the 1980s. Their nonproprietary names usually end in "-relin". The most well-known and widely used GnRH analogue is leuprorelin (brand name Lupron). GnRH analogues are available as generic medications. Despite this however, they continue to be very expensive.