Progestin in the context of Androgen receptor

The combined oral contraceptive pill (COCP), often referred to as the birth control pill or colloquially as "the pill", is a type of birth control that is designed to be taken orally by women. It is the oral form of combined hormonal contraception. The pill contains two important hormones: a progestin (a synthetic form of the hormone progestogen/progesterone) and estrogen (usually ethinylestradiol or 17β estradiol). When taken correctly, it alters the menstrual cycle to eliminate ovulation and prevent pregnancy.

Combined oral contraceptive pills were first approved for contraceptive use in the United States in 1960, and remain a very popular form of birth control. They are used by more than 100 million women worldwide including about 9 million women in the United States. From 2015 to 2017, 12.6% of women aged 15–49 in the US reported using combined oral contraceptive pills, making it the second most common method of contraception in this age range (female sterilization is the most common method). Use of combined oral contraceptive pills, however, varies widely by country, age, education, and marital status. For example, one third of women aged 16–49 in the United Kingdom use either the combined pill or progestogen-only pill (POP), compared with less than 3% of women in Japan (as of 1950–2014).

Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original hormonal method—the combined oral contraceptive pill—was first marketed as a contraceptive in 1960. In the ensuing decades, many other delivery methods have been developed, although the oral and injectable methods are by far the most popular. Hormonal contraception is highly effective: when taken on the prescribed schedule, users of steroid hormone methods experience pregnancy rates of less than 1% per year. Perfect-use pregnancy rates for most hormonal contraceptives are usually around the 0.3% rate or less. Currently available methods can only be used by women; the development of a male hormonal contraceptive is an active research area.

There are two main types of hormonal contraceptive formulations: combined methods which contain both an estrogen and a progestin, and progestogen-only methods which contain only progesterone or one of its synthetic analogues (progestins). Combined methods work by suppressing ovulation and thickening cervical mucus; while progestogen-only methods reduce the frequency of ovulation, most of them rely more heavily on changes in cervical mucus. The incidence of certain side effects is different for the different formulations: for example, breakthrough bleeding is much more common with progestogen-only methods. Certain serious complications occasionally caused by estrogen-containing contraceptives are not believed to be caused by progestogen-only formulations: deep vein thrombosis is one example of this.

Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. Ethinylestradiol is widely used for various indications such as the treatment of menopausal symptoms, gynecological disorders, and certain hormone-sensitive cancers. It is usually taken by mouth but is also used as a patch and vaginal ring.

The general side effects of ethinylestradiol include breast tenderness and enlargement, headache, fluid retention, and nausea among others. In males, ethinylestradiol can additionally cause breast development, feminization in general, hypogonadism, and sexual dysfunction. Rare but serious side effects include blood clots, liver damage, and cancer of the uterus.

Progestogen-only pills (POPs), colloquially known as "mini pills", are a type of oral contraceptive that contain synthetic progestogens (progestins) and do not contain estrogens. They are primarily used for the prevention of undesired pregnancy, although additional medical uses also exist.

Progestogen-only pills differ from combined oral contraceptive pills (COCPs), which consist of a combination of progestins and estrogens.

Norgestrel, sold under the brand name Opill among others, is a progestin which is used in birth control pills. It is often combined with the estrogen ethinylestradiol, marketed as Ovral. It is also used in menopausal hormone therapy. It is taken by mouth.

Side effects of norgestrel include menstrual irregularities, headaches, nausea, and breast tenderness. The most common side effects of the norgestrel include irregular bleeding, headaches, dizziness, nausea, increased appetite, abdominal pain, cramps, or bloating. Norgestrel is a progestin, or a synthetic progestogen, and hence is an agonist of the progesterone receptor, the biological target of progestogens like progesterone. It has weak androgenic activity and no other important hormonal activity.

Medroxyprogesterone acetate (MPA), also known as depot medroxyprogesterone acetate (DMPA) in injectable form and sold under the brand name Depo-Provera among others, is a hormonal medication of the progestin type. It is used as a method of birth control and as a part of menopausal hormone therapy. It is also used to treat endometriosis, abnormal uterine bleeding, paraphilia, and certain types of cancer. The medication is available both alone and in combination with an estrogen. It is taken by mouth, used under the tongue, or by injection into a muscle or fat.

Common side effects include menstrual disturbances such as absence of periods, abdominal pain, and headaches. More serious side effects include bone loss, blood clots, allergic reactions, and liver problems. Use is not recommended during pregnancy as it may harm the baby. MPA is an artificial progestogen, and as such activates the progesterone receptor, the biological target of progesterone. It also has androgenic activity and weak glucocorticoid activity. Due to its progestogenic activity, MPA decreases the body's release of gonadotropins and can suppress sex hormone levels. It works as a form of birth control by preventing ovulation.

Gonane (cyclopentanoperhydrophenanthrene) is a chemical compound with formula C
₁₇H
₂₈, whose structure consists of four hydrocarbon rings fused together: three cyclohexane units and one cyclopentane. It can also be viewed as the result of fusing a cyclopentane molecule with a fully hydrogenated molecule of phenanthrene, hence the more descriptive name "perhydrocyclopenta[a]phenanthrene". The non-systematic version of the above name is "cyclopentanoperhydrophenanthrene".

It has no double bonds, that is, it is completely saturated and is considered the main structure of steroids, often referred to as the steroid nucleus. There are many forms of gonane, but only a few occur naturally in living organisms. Some common forms include 5α-gonane and 5β-gonane. Estrane, androstane, and pregnane are derivatives of gonane with additional methyl or ethyl groups attached to certain carbon positions. The term gonane is also used to describe a group of progestins that are similar to levonorgestrel but have a slightly different structure than other hormones like estranes.

Progestogen-only injectable contraceptives (POICs) are a form of hormonal contraception and progestogen-only contraception that are administered by injection and providing long-lasting birth control. As opposed to combined injectable contraceptives, they contain only a progestogen without an estrogen, and include two progestin preparations:

• Medroxyprogesterone acetate (brand names Depo-Provera, Provera, Depo-subQ Provera 104) – 150 mg (intramuscularly) or 104 mg (subcutaneously) every 3 months
• Norethisterone enanthate (brand names NET EN, Noristerat, Norigest, Doryxas) – 200 mg (intramuscularly) every 2 months

Combined injectable contraceptives (CICs) are a form of hormonal birth control for women. They consist of monthly injections of combined formulations containing an estrogen and a progestin to prevent pregnancy.

CICs are different from progestogen-only injectable contraceptives (POICs), such as depot medroxyprogesterone acetate (DMPA; brand names Depo-Provera, Depo-SubQ Provera 104) and norethisterone enantate (NETE; brand name Noristerat), which are not combined with an estrogen and are given once every two to three months instead of once a month.

Bioidentical hormone replacement therapy (BHRT), also known as bioidentical hormone therapy (BHT) or natural hormone therapy, is the use of hormones that are identical on a molecular level with endogenous hormones in hormone replacement therapy. It may also be combined with blood and saliva testing of hormone levels, and the use of pharmacy compounding to obtain hormones in an effort to reach a targeted level of hormones in the body. A number of claims by some proponents of BHT have not been confirmed through scientific testing. Specific hormones used in BHT include estrone, estradiol, progesterone, testosterone, dehydroepiandrosterone (DHEA), and estriol.

Custom-compounded BHT is a practice almost wholly restricted to the United States and is a form of alternative medicine. It has been promoted as a panacea for many diseases and for relieving the symptoms of menopause beyond the medical objective of reducing the risk of osteoporosis. There is little evidence to support these incremental claims; the hormones are expected to have the same risks and benefits as comparable approved drugs for which there is evidence based on extensive research and regulation, except for progesterone, which may have an improved safety profile than artificial progestogens, though direct comparisons with progestins have not been made. Risks associated with the less-controlled process of compounding bioidentical hormones are not clearly understood. In addition, the accuracy and efficacy of saliva testing have not been definitively proven, and the long-term effects of using blood testing to reach target levels of hormones have not been researched.

Norethisterone, also known as norethindrone and sold under the brand name Norlutin among others, is a progestin medication used in birth control pills, menopausal hormone therapy, and for the treatment of gynecological disorders. The medication is available in both low-dose and high-dose formulations and both alone and in combination with an estrogen. It is used by mouth or, as norethisterone enanthate, by injection into muscle.

Side effects of norethisterone include menstrual irregularities, headaches, nausea, breast tenderness, mood changes, acne, increased hair growth. Norethisterone is a progestin, or a synthetic progestogen, and hence is an agonist of the progesterone receptor, the biological target of progestogens like progesterone. It has weak androgenic and estrogenic activity, mostly at high dosages, and no other important hormonal activity.

Estradiol (E2) is a medication and naturally occurring steroid hormone. It is an estrogen and is used mainly in menopausal hormone therapy and to treat low sex hormone levels in women. It is also used in hormonal birth control for women, in feminizing hormone therapy for transgender women and some non-binary individuals, and in the treatment of hormone-sensitive cancers like prostate cancer in men and breast cancer in women, among other uses. Estradiol can be taken by mouth, held and dissolved under the tongue, as a gel or patch that is applied to the skin, in through the vagina, by injection into muscle or fat, or through the use of an implant that is placed into fat, among other routes.

Side effects of estradiol in women include breast tenderness, breast enlargement, headache, fluid retention, and nausea among others. Men and children who are exposed to estradiol may develop symptoms of feminization, such as breast development and a feminine pattern of fat distribution, and men may also experience low testosterone levels and infertility. Estradiol may increase the risk of endometrial hyperplasia and endometrial cancer in women with intact uteruses if it is not taken together with a progestogen such as progesterone. The combination of estradiol with a progestin, though not with oral progesterone, may increase the risk of breast cancer. Estradiol should not be used in women who are pregnant or breastfeeding or who have breast cancer, among other contraindications.

Conjugated estrogens (CEs), or conjugated equine estrogens (CEEs), sold under the brand name Premarin among others, is an estrogen medication which is used in menopausal hormone therapy and for various other indications. It is a mixture of the sodium salts of estrogen conjugates found in horses, such as estrone sulfate and equilin sulfate. CEEs are available in the form of both natural preparations manufactured from the urine of pregnant mares and fully synthetic replications of the natural preparations. They are formulated both alone and in combination with progestins such as medroxyprogesterone acetate. CEEs are usually taken by mouth, but can also be given by application to the skin or vagina as a cream or by injection into a blood vessel or muscle.

Side effects of CEEs include breast tenderness and enlargement, headache, fluid retention, and nausea among others. It may increase the risk of endometrial hyperplasia and endometrial cancer in women with an intact uterus if it is not taken together with a progestogen like progesterone. The medication may also increase the risk of blood clots, cardiovascular disease, and, when combined with most progestogens, breast cancer. CEEs are estrogens, or agonists of the estrogen receptor, the biological target of estrogens like estradiol. Compared to estradiol, certain estrogens in CEEs are more resistant to metabolism, and the medication shows relatively increased effects in certain parts of the body like the liver. This results in an increased risk of blood clots and cardiovascular problems with CEEs relative to estradiol.