Estriol (E3), also spelled oestriol, is a steroid, a weak estrogen, and a minor female sex hormone. It is one of three major endogenous estrogens, the others being estradiol and estrone. Levels of estriol in women who are not pregnant are almost undetectable. However, during pregnancy, estriol is synthesized in very high quantities by the placenta and is the most produced estrogen in the body by far, although circulating levels of estriol are similar to those of other estrogens due to a relatively high rate of metabolism and excretion. Relative to estradiol, both estriol and estrone have far weaker activity as estrogens.
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was 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.
Norethisterone acetate (NETA), also known as norethindrone acetate and sold under the brand name Primolut-Nor among others, is a progestin medication which is used in birth control pills, menopausal hormone therapy, and for the treatment of gynecological disorders. The medication available in low-dose and high-dose formulations and is used alone or in combination with an estrogen. It is ingested orally.
Norelgestromin, or norelgestromine, sold under the brand names Evra and Ortho Evra among others, is a progestin medication which is used as a method of birth control for women. The medication is available in combination with an estrogen and is not available alone. It is used as a patch that is applied to the skin.
Norgestimate, sold under the brand names Ortho Tri-Cyclen and Previfem among others, is a progestin medication which is used in birth control pills for women and in menopausal hormone therapy. The medication is available in combination with an estrogen and is not available alone. 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.
Algestone acetophenide, also known more commonly as dihydroxyprogesterone acetophenide (DHPA) and sold under the brand names Perlutal and Topasel among others, is a progestin medication which is used in combination with an estrogen as a form of long-lasting injectable birth control. It has also been used alone, but is no longer available as a standalone medication. DHPA is not active by mouth and is given once a month by injection into muscle.
Norethisterone enanthate (NETE), also known as norethindrone enanthate, is a form of hormonal birth control which is used to prevent pregnancy in women. It is used both as a form of progestogen-only injectable birth control and in combined injectable birth control formulations. It may be used following childbirth, miscarriage, or abortion. The failure rate per year in preventing pregnancy for the progestogen-only formulation is 2 per 100 women. Each dose of this form lasts two months with only up to two doses typically recommended.
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.
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.
Estradiol sulfate (E2S), or 17β-estradiol 3-sulfate, is a natural, endogenous steroid and an estrogen ester. E2S itself is biologically inactive, but it can be converted by steroid sulfatase into estradiol, which is a potent estrogen. Simultaneously, estrogen sulfotransferases convert estradiol to E2S, resulting in an equilibrium between the two steroids in various tissues. Estrone and E2S are the two immediate metabolic sources of estradiol. E2S can also be metabolized into estrone sulfate (E1S), which in turn can be converted into estrone and estradiol. Circulating concentrations of E2S are much lower than those of E1S. High concentrations of E2S are present in breast tissue, and E2S has been implicated in the biology of breast cancer via serving as an active reservoir of estradiol.
Estradiol diundecylenate, or estradiol diundecenoate, also known as 17β-estradiol 3,17β-diundec-10-enoate, is a semisynthetic steroidal estrogen and an estrogen ester – specifically, the 3,17β-diundecylenate ester of estradiol – which was previously marketed in Argentina.
8,9-Dehydroestrone, or Δ8-estrone, also known as estra-1,3,5(10),8-tetraen-3-ol-17-one, is a naturally occurring estrogen found in horses which is closely related to equilin, equilenin, and estrone, and, as the 3-sulfate ester sodium salt, is a minor constituent (3.5%) of conjugated estrogens (Premarin). It produces 8,9-dehydro-17β-estradiol as an important active metabolite, analogously to conversion of estrone or estrone sulfate into estradiol. The compound was first described in 1997. In addition to 8,9-dehydroestrone and 8,9-dehydro-17β-estradiol, 8,9-dehydro-17α-estradiol is likely also to be present in conjugated estrogens, but has not been identified at this time.
16α-Hydroxyestrone (16α-OH-E1), or hydroxyestrone, also known as estra-1,3,5(10)-triene-3,16α-diol-17-one, is an endogenous steroidal estrogen and a major metabolite of estrone, as well as an intermediate in the biosynthesis of estriol. It is a potent estrogen similarly to estrone, and it has been suggested that the ratio of 16α-hydroxyestrone to 2-hydroxyestrone, the latter being much less estrogenic in comparison and even antiestrogenic in the presence of more potent estrogens like estradiol, may be involved in the pathophysiology of breast cancer. Conversely, 16α-hydroxyestrone may help to protect against osteoporosis.
8,9-Dehydroestradiol, or Δ8-17β-estradiol, also known as estra-1,3,5(10),8-tetraen-17β-ol-3-one, is a naturally occurring steroidal estrogen found in horses which is closely related to equilin, equilenin, and estradiol, and, as the 3-sulfate ester sodium salt, is a minor constituent of conjugated estrogens (Premarin). It is also an important active metabolite of 8,9-dehydroestrone, analogously to conversion of estrone or estrone sulfate into estradiol.
Estrone sulfate (E1S) is an estrogen medication and naturally occurring steroid hormone. It is used in menopausal hormone therapy among other indications. As the sodium salt, it is the major estrogen component of conjugated estrogens (Premarin) and esterified estrogens. In addition, E1S is used on its own as the piperazine salt estropipate. The compound also occurs as a major and important metabolite of estradiol and estrone. E1S is most commonly taken by mouth, but in the form of Premarin can also be taken by parenteral routes such as transdermal, vaginal, and injection.
Ethinylestradiol sulfate, also known as 17α-ethynylestradiol 3-sulfate, is an estrogen ester – specifically, the C3 sulfuric acid (sulfate) ester of the synthetic estrogen ethinylestradiol (EE) – and is the major metabolite of EE. Circulating levels of EE sulfate range from 6 to 22 times those of EE when EE is taken orally. EE sulfate can be transformed back into EE (14–21%) via steroid sulfatase, and it has been suggested that EE sulfate may serve as a circulating reservoir for EE, similarly to the case of estrone sulfate with estradiol. However, the EE sulfate pool with EE is far smaller than the pool of estrone sulfate that occurs with estradiol. In addition, in contrast to the case of estrone sulfate and estrone, the conversion rate of EE sulfate back into EE is relatively low, and has been said probably isn't of clinical significance. However, other studies have suggested that EE sulfate may nonetheless contribute up to 20% of total EE levels.
Equine estrogens, or horse estrogens, are estrogens found in horses. They include the following:
Estradiol benzoate/progesterone (EB/P4), sold under the brand names Duogynon and Sistocyclin among others, is a combination medication of estradiol benzoate (EB), an estrogen, and progesterone (P4), a progestogen. It has been formulated both as short-acting oil solutions and long-acting microcrystalline aqueous suspensions and is given by injection into muscle either once or continuously at regular intervals.
