Anordrin (former developmental code name AF-53), also known as 2α,17α-diethynyl-A-nor-5α-androstane-2β,17β-diol dipropionate, is a

synthetic Synthetic may refer to: Science * Synthetic biology * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic elements, chemical elements that are not naturally found on Earth and therefore have to be created in ...

steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...

selective estrogen receptor modulator Selective estrogen receptor modulators (SERMs), also known as estrogen receptor agonists/antagonists (ERAAs), are a class of drugs that act on estrogen receptors (ERs). Compared to pure ER agonists–antagonists (e.g., full agonists and silent ...

(SERM) which is used in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

as an

emergency contraceptive Emergency contraception (EC) is a birth control measure, used after sexual intercourse to prevent pregnancy. There are different forms of EC. Emergency contraceptive pills (ECPs), sometimes simply referred to as emergency contraceptives (ECs), ...

. It is the most commonly used emergency contraceptive in China. The drug is marketed in a combination formulation with

mifepristone Mifepristone, and also known by its developmental code name RU-486, is a drug typically used in combination with misoprostol to bring about a medical abortion during pregnancy. This combination is 97% effective during the first 63 days (9 wee ...

under the brand name Zi Yun. Anordrin has not been studied for use or marketed outside of China. It has been used in China since the 1970s. Anordrin has both weak

estrogen Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...

ic and

antiestrogen Antiestrogens, also known as estrogen antagonists or estrogen blockers, are a class of drugs which prevent estrogens like estradiol from mediating their biological effects in the body. They act by blocking the estrogen receptor (ER) and/or inh ...

ic activity. It binds to the

estrogen receptor Estrogen receptors (ERs) are proteins found in cell (biology), cells that function as receptor (biochemistry), receptors for the hormone estrogen (17β-estradiol). There are two main classes of ERs. The first includes the intracellular estrogen ...

but does not bind to the

androgen receptor The androgen receptor (AR), also known as NR3C4 (nuclear receptor subfamily 3, group C, member 4), is a type of nuclear receptor that is activated by binding any of the androgenic hormones, including testosterone and dihydrotestosterone, in th ...

or the

progesterone receptor The progesterone receptor (PR), also known as NR3C3 or nuclear receptor subfamily 3, group C, member 3, is a protein found inside cells. It is activated by the steroid hormone progesterone. In humans, PR is encoded by a single ''PGR'' gene resi ...

. In animals, anordrin has

antigonadotropic An antigonadotropin is a drug which suppresses the activity and/or downstream effects of one or both of the gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). This results in an inhibition of the hypothalamic-pituita ...

effects, and in male animals, inhibits

spermatogenesis Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testicle. This process starts with the Mitosis, mitotic division of the stem cells located close to the basement membrane of ...

and causes

atrophy Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), malnutrition, poor nourishment, poor circulatory system, circulation, loss of hormone, ...

of the

epididymis The epididymis (; : epididymides or ) is an elongated tubular genital organ attached to the posterior side of each one of the two male reproductive glands, the testicles. It is a single, narrow, tightly coiled tube in adult humans, in length; ...

prostate The prostate is an male accessory gland, accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemica ...

, and

seminal vesicle The seminal vesicles (also called vesicular glands or seminal glands) are a pair of convoluted tubular accessory glands that lie behind the urinary bladder of male mammals. They secrete fluid that largely composes the semen. The vesicles are 5 ...

s. It produces a dihydroxylated

active metabolite An active metabolite, or pharmacologically active metabolite is a biologically active metabolite of a xenobiotic substance, such as a drug or environmental chemical. Active metabolites may produce therapeutic effects, as well as harmful effects. ...

, anordiol, with similar but more potent estrogenic activity. The

abortifacient An abortifacient ("that which will cause a miscarriage" from Latin: '' abortus'' "miscarriage" and '' faciens'' "making") is a substance that induces abortion. This is a nonspecific term which may refer to any number of substances or medications, ...

effects of anordrin in animals are blocked by supplemental

estradiol Estradiol (E2), also called oestrogen, oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of female reproductive cycles such as estrous and menstrual cycles. Estradiol is responsible ...

, suggesting that it is acting as an antiestrogen rather than an estrogen to exert its emergency contraceptive effects. The drug is also referred to as ''tanqinyao'', "the Chinese vacation pill" or "the pill for visiting relatives," given that it is a recommended contraception method for couples who have frequent sex within a short period, as may be the case for Chinese couples who live apart for most of the year due to work. Anordrin is not approved for use in the United States because each pill is near, or in excess of, the total monthly maximum allowable hormone dose in the American system.

References

{{Estrogen receptor modulators Ethynyl compounds Androstanes Propionate esters Selective estrogen receptor modulators Synthetic estrogens

See also

References