Androstenediol, or 5-androstenediol (abbreviated as A5 or Δ⁵-diol), also known as androst-5-ene-3β,17β-diol, is an

endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ...

weak

androgen An androgen (from Greek ''andr-'', the stem of the word meaning ) is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes ...

and

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 ...

steroid hormone A steroid hormone is a steroid that acts as a hormone. Steroid hormones can be grouped into two classes: corticosteroids (typically made in the adrenal cortex, hence ''cortico-'') and sex steroids (typically made in the gonads or placenta). Wit ...

and intermediate in the

biosynthesis Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme-Catalysis, catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthe ...

testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...

from

dehydroepiandrosterone Dehydroepiandrosterone (DHEA), also known as androstenolone, is an endogenous steroid hormone precursor. It is one of the most abundant circulating steroids in humans. DHEA is produced in the adrenal glands, the gonads, and the brain. It funct ...

(DHEA). It is closely related to

androstenedione Androstenedione, or 4-androstenedione (abbreviated as A4 or Δ4-dione), also known as androst-4-ene-3,17-dione, is an endogenous weak androgen steroid hormone and intermediate in the biosynthesis of estrone and of testosterone from dehydroe ...

(androst-4-ene-3,17-dione).

Biological activity

Androstenediol is a direct

metabolite In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, c ...

of the most abundant

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 ...

produced by the human

adrenal cortex The adrenal cortex is the outer region and also the largest part of the adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones. I ...

, DHEA. It is less

ic than the related compound, Δ⁴-androstenediol, and has been found to stimulate the

immune system The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to bacteria, as well as Tumor immunology, cancer cells, Parasitic worm, parasitic ...

. When administered to

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...

s, androstenediol, ''

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, an ...

'', has approximately 1.4% of the

icity of DHEA, 0.54% of the androgenicity of

, and 0.21% of the androgenicity of testosterone. Androstenediol possesses potent

ic activity, similarly to DHEA and 3β-androstanediol. It has approximately 6% and 17% of the

affinity Affinity may refer to: Commerce, finance and law * Affinity (law), kinship by marriage * Affinity analysis, a market research and business management technique * Affinity Credit Union, a Saskatchewan-based credit union * Affinity Equity Pa ...

of estradiol at the ERα and

ERβ Estrogen receptor beta (ERβ) also known as NR3A2 (nuclear receptor subfamily 3, group A, member 2) is one of two main types of estrogen receptor—a nuclear receptor which is activated by the sex hormone estrogen. In humans ERβ is encoded by t ...

, respectively. Although androstenediol has far lower affinity for the ERs compared to the major estrogen

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 ...

, it circulates at approximately 100-fold higher concentrations, and so is thought may play a significant role as an estrogen in the body.

Chemistry

Androstenediol, also known as androst-5-ene-3β,17β-diol, is a

naturally occurring A natural product is a natural compound or substance produced by a living organism—that is, found in nature. In the broadest sense, natural products include any substance produced by life. Natural products can also be prepared by chemical ...

androstane

. It is closely related structurally to

(A4; androst-4-ene-3,17-dione),

(DHEA; androst-5-en-3β-ol-17-one), and

(androst-4-en-17β-ol-3-one), as well as to 3β-androstanediol (5α-androstane-3β,17β-diol).

Derivative In mathematics, the derivative is a fundamental tool that quantifies the sensitivity to change of a function's output with respect to its input. The derivative of a function of a single variable at a chosen input value, when it exists, is t ...

s and analogues of androstenediol, such as the 17α-substituted methandriol (17α-methylandrostenediol) and ethinylandrostenediol (17α-ethynylandrostenediol) as well as the naturally occurring 19-norandrostane derivative norandostenediol (19-nor-5-androstenediol), have been synthesized and studied. Methandriol and its

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

s are

s and

anabolic steroid Anabolic steroids, also known as anabolic-androgenic steroids (AAS), are a class of drugs that are structurally related to testosterone, the main male sex hormone, and produce effects by binding to the androgen receptor (AR). Anabolism, Anaboli ...

s while ethinylandrostenediol is an estrogen.

Research

Radiation countermeasure

Androstenediol has been investigated for use as a radiation countermeasure. Its value as a radiation countermeasure is based mainly on its stimulation of production of

white blood cell White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign entities. White blood cells are genera ...

s and

platelet Platelets or thrombocytes () are a part of blood whose function (along with the coagulation#Coagulation factors, coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a thrombus, blood clot. Platelets have no ...

s. Its potential use as a

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

countermeasure was developed by the Armed Forces Radiobiology Research Institute (AFRRI) and subsequently studied by AFRRI and Hollis-Eden Pharmaceuticals under the proposed brand name Neumune for the treatment of

acute radiation syndrome Acute radiation syndrome (ARS), also known as radiation sickness or radiation poisoning, is a collection of health effects that are caused by being exposed to high amounts of ionizing radiation in a short period of time. Symptoms can start wit ...

. The

clinical trial Clinical trials are prospective biomedical or behavioral research studies on human subject research, human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel v ...

s with

rhesus monkey The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies split between two groups, the Chinese-derived and the Indian-derived. Generally brown or g ...

s were successful. According to the Hollis-Eden report, only 12.5% of the 40 Neumune-treated animals died versus 32.5% in the

placebo A placebo ( ) can be roughly defined as a sham medical treatment. Common placebos include inert tablets (like sugar pills), inert injections (like saline), sham surgery, and other procedures. Placebos are used in randomized clinical trials ...

group. Hollis-Eden had applied for a contract from the U.S. Government under the BioShield Request for Proposals (RFP) for radiation countermeasures. After being encouraged for 2.5 years that Neumune was in the competitive range, on March 9, 2007, the RFP was canceled by HHS. According to HHS, "the product was no longer in the competitive range".US cancels radiation contract with Hollis-Eden
, March 9, 2007 No further explanation was given. As a result, Hollis-Eden has now withdrawn from the radiation countermeasure field.

Additional images

References

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Biological activity In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or ...

, titlestyle = background:#ccccff , list1 = {{Androgen receptor modulators {{Estrogen receptor modulators {{Xenobiotic-sensing receptor modulators Anabolic–androgenic steroids Androstanes Estrogens Pregnane X receptor agonists Selective ERβ agonists