Ethisterone

A progestogen hormone

Chemical structure of Ethisterone

Ethisterone, also known as 17α-ethinyltestosterone, is a progestogen hormone and a synthetic steroid with progestogenic activity. It was one of the first orally active progestogens to be synthesized and used in medicine. Ethisterone is a derivative of testosterone and is closely related to other progestogens such as norethisterone.

History

Ethisterone was first synthesized in 1938 by the German chemist Hans Herloff Inhoffen and his colleagues. It was introduced for medical use in the 1940s and was one of the earliest progestogens to be used in hormone replacement therapy and contraception.

Chemical Structure

Ethisterone is a synthetic androgen and progestogen that is structurally related to testosterone. It is characterized by the presence of an ethinyl group at the C17α position of the steroid nucleus, which is responsible for its oral activity.

Ball-and-stick model of Ethisterone molecule

Mechanism of Action

Ethisterone acts as a progestogen by binding to the progesterone receptor in target tissues. This binding mimics the effects of natural progesterone, leading to changes in the endometrium and regulation of the menstrual cycle. It also has weak androgenic activity due to its structural similarity to testosterone.

Medical Uses

Ethisterone was historically used in the treatment of menstrual disorders, endometriosis, and as a component of oral contraceptives. However, its use has declined with the development of newer progestogens with improved safety and efficacy profiles.

Side Effects

The side effects of ethisterone are similar to those of other progestogens and may include nausea, headache, breast tenderness, and mood changes. Due to its androgenic activity, it may also cause acne and hirsutism in some users.

Pharmacokinetics

Ethisterone is well absorbed when taken orally and undergoes extensive first-pass metabolism in the liver. It is metabolized primarily by the cytochrome P450 enzyme system and is excreted in the urine.

Related Compounds

Ethisterone is related to other synthetic progestogens such as norethisterone and medroxyprogesterone acetate. These compounds have been developed to improve the pharmacokinetic and pharmacodynamic properties of progestogens.

Related Pages

• Progestogen
• Hormone replacement therapy
• Oral contraceptive
• Testosterone