Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the major progestogen in the body. Progesterone has a variety of important functions in the body. It is also a crucial metabolic intermediate in the production of other endogenous steroids, including the sex hormones and the corticosteroids, and plays an important role in brain function as a neurosteroid.
Progestogens, also sometimes written progestagens or gestagens, are a class of natural or synthetic steroid hormones that bind to and activate the progesterone receptors (PR). Progesterone is the major and most important progestogen in the body. The progestogens are named for their function in maintaining pregnancy, although they are also present at other phases of the estrous and menstrual cycles.
A progestogen, also referred to as a progestagen, gestagen, or gestogen, is a type of medication which produces effects similar to those of the natural female sex hormone progesterone in the body. A progestin is a synthetic progestogen. Progestogens are used most commonly in hormonal birth control and menopausal hormone therapy. They can also be used in the treatment of gynecological conditions, to support fertility and pregnancy, to lower sex hormone levels for various purposes, and for other indications. Progestogens are used alone or in combination with estrogens. They are available in a wide variety of formulations and for use by many different routes of administration. Examples of progestogens include natural or bioidentical progesterone as well as progestins such as medroxyprogesterone acetate and norethisterone.
Metandienone, also known as methandienone or methandrostenolone and sold under the brand name Dianabol (D-Bol) among others, is an androgen and anabolic steroid (AAS) medication which is still quite often used because of its affordability and effectiveness for bulking cycles. It is also used non-medically for physique- and performance-enhancing purposes. It is often taken by mouth.
Tibolone, sold under the brand name Livial among others, is a medication which is used in menopausal hormone therapy and in the treatment of postmenopausal osteoporosis and endometriosis. The medication is available alone and is not formulated or used in combination with other medications. It is taken by mouth.
Norethisterone, also known as norethindrone and sold under many brand names, 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.
Dydrogesterone, sold under the brand name Duphaston, Dydroboon among others, is a progestin medication which is used for a variety of indications, including threatened or recurrent miscarriage during pregnancy, dysfunctional bleeding, infertility due to luteal insufficiency, dysmenorrhea, endometriosis, secondary amenorrhea, irregular cycles, premenstrual syndrome, and as a component of menopausal hormone therapy. It is taken by mouth.
5α-Dihydroprogesterone is an endogenous progestogen and neurosteroid that is synthesized from progesterone. It is also an intermediate in the synthesis of allopregnanolone and isopregnanolone from progesterone.
Estetrol (E4), or oestetrol, is one of the four natural estrogenic steroid hormones found in humans, along with estrone (E1), estradiol (E2), and estriol (E3), estetrol is a major estrogen in the body. In contrast to estrone and estradiol, estetrol is a native estrogen of fetal life. Estetrol is produced exclusively by the fetal liver and is found in dectable levels only during pregnancy, with relatively high levels in the fetus and lower levels in the maternal circulation.
Promegestone, sold under the brand name Surgestone, is a progestin medication which is used in menopausal hormone therapy and in the treatment of gynecological disorders. It is taken by mouth.
Normethandrone, also known as methylestrenolone or methylnortestosterone and sold under the brand name Metalutin among others, is a progestin and androgen/anabolic steroid (AAS) medication which is used in combination with an estrogen in the treatment of amenorrhea and menopausal symptoms in women. It is taken by mouth.
Nomegestrol acetate (NOMAC), sold under the brand names Lutenyl and Zoely among others, is a progestin medication which is used in birth control pills, menopausal hormone therapy, and for the treatment of gynecological disorders. It is available both alone and in combination with an estrogen. NOMAC is taken by mouth. A birth control implant for placement under the skin was also developed but ultimately was not marketed.
3β-Androstanediol, also known as 5α-androstane-3β,17β-diol, and sometimes shortened in the literature to 3β-diol, is an endogenous steroid hormone and a metabolite of androgens like dehydroepiandrosterone (DHEA) and dihydrotestosterone (DHT).
Trengestone, sold under the brand names Reteroid, Retroid, and Retrone, is a progestin medication which was formerly used to treat menstrual disorders but is now no longer marketed. It is taken by mouth.
20α-Dihydroprogesterone (20α-DHP), also known as 20α-hydroxyprogesterone (20α-OHP), is a naturally occurring, endogenous progestogen. It is a metabolite of progesterone, formed by the 20α-hydroxysteroid dehydrogenases (20α-HSDs) AKR1C1, AKR1C2, and AKR1C3 and the 17β-hydroxysteroid dehydrogenase (17β-HSD) HSD17B1. 20α-DHP can be transformed back into progesterone by 20α-HSDs and by the 17β-HSD HSD17B2. HSD17B2 is expressed in the human endometrium and cervix among other tissues. In animal studies, 20α-DHP has been found to be selectively taken up into and retained in target tissues such as the uterus, brain, and skeletal muscle.
5β-Dihydroprogesterone is an endogenous neurosteroid and an intermediate in the biosynthesis of pregnanolone and epipregnanolone from progesterone. It is synthesized from progesterone by the enzyme 5β-reductase.
Retroprogesterone, also known as 9β,10α-progesterone or as 9β,10α-pregn-4-ene-3,20-dione, is a progestin which was never marketed. It is a stereoisomer of the naturally occurring progestogen progesterone, in which the hydrogen atom at the 9th carbon is in the α-position instead of the β-position and the methyl group at the 10th carbon is in the β-position instead of the α-position. In other words, the atom positions at the two carbons have been reversed relative to progesterone, hence the name retroprogesterone. This reversal results in a "bent" configuration in which the plane of rings A and B is orientated at a 60° angle below the rings C and D. This configuration is ideal for interaction with the progesterone receptor, with retroprogesterone binding with high affinity to this receptor. However, the configuration is not as ideal for binding to other steroid hormone receptors, and as a result, retroprogesterone derivatives have increased selectivity for the progesterone receptor relative to progesterone.
Methylestradiol, sold under the brand names Ginecosid, Ginecoside, Mediol, and Renodiol, is an estrogen medication which is used in the treatment of menopausal symptoms. It is formulated in combination with normethandrone, a progestin and androgen/anabolic steroid medication. Methylestradiol is taken by mouth.
Quingestrone, also known as progesterone 3-cyclopentyl enol ether (PCPE) and sold under the brand name Enol-Luteovis, is a progestin medication which was previously used in birth control pills in Italy but is now no longer marketed. It is taken by mouth.
2-Hydroxyestrone (2-OHE1), also known as estra-1,3,5(10)-trien-2,3-diol-17-one, is an endogenous, naturally occurring catechol estrogen and a major metabolite of estrone and estradiol. It is formed irreversibly from estrone in the liver and to a lesser extent in other tissues via 2-hydroxylation mediated by cytochrome P450 enzymes, mainly the CYP3A and CYP1A subfamilies. 2-OHE1 is the most abundant catechol estrogen in the body.
