Androstenedione

From Wikipedia, the free encyclopedia
  (Redirected from 4-androstenedione)
Jump to: navigation, search
To be distinguished from 1-Androstenedione, Androstanedione, or Androstenediol.
Androstenedione
Androstendion.svg
Androstediona3D.png
Systematic (IUPAC) name
4-Androstene-3,17-dione
Clinical data
Legal status Schedule III (US)
Pharmacokinetic data
Metabolism Liver
Identifiers
CAS number 63-05-8 YesY
ATC code None
PubChem CID 6128
IUPHAR ligand 2860
DrugBank DB01536
ChemSpider 5898 YesY
UNII 409J2J96VR YesY
ChEBI CHEBI:16422 YesY
ChEMBL CHEMBL274826 YesY
Chemical data
Formula C19H26O2 
Mol. mass 286.4
 YesY (what is this?)  (verify)

Androstenedione (4-androstenedione, 17-ketotestosterone) is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol.

Synthesis[edit]

Steroidogenesis. Androstenedione is at center.

Androstenedione is the common precursor of male and female sex hormones.[1] Some androstenedione is also secreted into the plasma, and may be converted in peripheral tissues to testosterone and estrogens.

Androstenedione can be synthesized in one of two ways. The primary pathway involves conversion of 17-hydroxypregnenolone to dehydroepiandrosterone by way of 17,20-lyase, with subsequent conversion of dehydroepiandrosterone to androstenedione via the enzyme 3-β-hydroxysteroid dehydrogenase. The secondary pathway involves conversion of 17-hydroxyprogesterone, most often a precursor to cortisol, to androstenedione directly by way of 17,20-lyase. Thus, 17,20-lyase is required for the synthesis of androstenedione, whether immediately or one step removed.

The production of adrenal androstenedione is governed by ACTH, whereas production of gonadal androstenedione is under control by gonadotropins. In premenopausal women, the adrenal glands and ovaries each produce about half of the total androstenedione(about 3 mg/day). After menopause, androstenedione production is about halved, due primarily to the reduction of the steroid secreted by the ovary. Nevertheless, androstenedione is the principal steroid produced by the postmenopausal ovary.

Endocrine function[edit]

Androstenedione is further converted to either testosterone or estrogen.

In males, conversion of androstenedione to testosterone requires the enzyme 17β-hydroxysteroid dehydrogenase.

In females, androstenedione is released into the blood by theca cells. Conversion of androstenedione to estrogen (e.g., estrone and estradiol) requires the enzyme aromatase. Androstenedione is a substrate for estrogen production in granulosa cells which produce aromatase. Thus, theca cells and granulosa cells work together to form estrogens.[2]

Levels are normally 30-200 ng/dL (1.0-7.0 nmol/l) in females and 40-150 ng/dL (1.4-5.2 nmol/l) in males.[3]

Androstenedione as a supplement[edit]

History[edit]

Androstenedione was manufactured as a dietary supplement, often called andro (or andros) for short. Sports Illustrated credits Patrick Arnold for introducing androstenedione to the North American market.[4] Andro was legal and able to be purchased over the counter, and, as a consequence, it was in common use in Major League Baseball throughout the 1990s by record-breaking sluggers like Mark McGwire. The supplement is banned by the World Anti-Doping Agency, and from the Olympic Games.

The International Olympic Committee in 1997 banned androstenedione and placed it under the category of androgenic-anabolic steroids.[5]

Androstenedione is banned by MLB, the NFL, USOC, NCA, and by the NBA.[5]

Barry R. McCaffrey, the director of the White House's Office of National Drug Control Policy, attempted to determine whether androstenedione could be classified as an anabolic steroid in July 1999. However, he could not because there is no proof of it promoting muscle growth.[5] Now it is known that human bodies require an equal amount of testosterone and androstenedione. The supplement of androstenedione works by increasing the amount of androstenedione which in turn increases the amount of testosterone in the body and then the effects are similar to those of anabolic steroids. [6]

On March 12, 2004, the Anabolic Steroid Control Act of 2004 was introduced into the United States Senate. It amended the Controlled Substance Act to place both anabolic steroids and prohormones on a list of controlled substances, making possession of the banned substances a federal crime. The law took effect on January 20, 2005. However, androstenedione was legally defined as an anabolic steroid, even though there is scant evidence that androstenedione itself is anabolic in nature.

On April 11, 2004, the United States Food and Drug Administration banned the sale of androstenedione, citing that the drug poses significant health risks commonly associated with steroids. The side effects for men include breast development, behavioral changes, heart disease, and more. Side effects for women are similar to the side effects from anabolic steroids in that their voices will deepen and they may grow facial hair since both occur from an increase level of testosterone. Another side effect of androstenedione is male pattern baldness. The main psychological side effect of androstenedione is depression. Mood swings are also common of any user. [7]

Androstenedione is currently banned by the U.S. military.[8]

Biological effects[edit]

Androstenedione has been shown to increase serum testosterone levels over an eight-hour period in men when taken as a single oral dose of 300 mg per day, but a dose of 100 mg had no significant effect on serum testosterone. However, serum levels of estradiol increased following both the 100 mg and 300 mg doses. The study also reported that the serum level of estrogens and testosterone produced varied widely between individuals.[9] A 2006 review paper summarized several studies that examined the effect of androstenedione on strength training. At dosages of 50 mg or 100 mg per day, andro had no effect on muscle strength or size, or on body fat levels. One study used a daily dosage of 300 mg of androstenedione combined with several other supplements, and also found no increase in strength when compared to a control group that did not take the supplements. The review authors speculate that sufficiently high doses may indeed lead to increased muscle size and strength. However, due to the federal ban on androstenedione supplements, it is difficult to carry out new research on its positive and negative effects. The review authors conclude that individuals should not use androstenedione supplements due to the lack of evidence of beneficial effects, the wide variation in individual responses to the supplement, and the risk of unknown side-effects.[10]

Because androstenedione can be converted to estrogenic steroids, people taking this supplement may have estrogenic side-effects.[citation needed] In child development, higher levels of androstenedione in boys has been associated with higher levels of acting out behaviours. [11][page needed][non-primary source needed][better source needed]

In addition to its role as a precursor to testosterone in the body, androstenedione has androgenic properties in its own right, acting as a weak partial agonist of the androgen receptor.[12][non-primary source needed][better source needed] However, in the presence of full agonists like testosterone or dihydrotestosterone (DHT), due to its lower intrinsic activity in comparison, it has antagonistic properties, and can behave more like an antiandrogen like cyproterone.[12][non-primary source needed][better source needed] One study has shown that the supplement "Andro" (a mixture of androstenedione and androstenediol) does not significantly increase muscle mass or strength.[importance?][13][14][non-primary source needed][better source needed][15][bare URL][better source needed]

Additional images[edit]

References[edit]

  1. ^ Devlin, edited by Thomas M. (2010). Textbook of biochemistry : with clinical correlations (7th ed. ed.). Hoboken, NJ: John Wiley & Sons. p. 432. ISBN 0470281731. 
  2. ^ Medical Physiology, Boron & Boulpaep, ISBN 1-4160-2328-3, Elsevier Saunders 2005. Updated edition. Page 1155
  3. ^ Androstenedione, Serum from Mayo Clinic. Retrieved march 2014
  4. ^ "Is This Dr. Evil?". CNN. October 9, 2006. 
  5. ^ a b c Reents, S. Sport and Exercise Pharmacology; Human Kinetics: Champaign, IL, 2000
  6. ^ Cole, Adam. "How Does Androstenedione Work?". livestrong.com. Retrieved 14 March 2013. 
  7. ^ "Find a Vitamin or Supplement". WebMD. Retrieved 14 March 2013. 
  8. ^ USAF Medical Service Home Page
  9. ^ Leder, B.; Longcope, C.; Catlin, D.; Ahrens, B. Shoenfeld; Finkelstein, J. "Oral Androstenedione Administration and Serum Testosterone Concentrations in Young Men". JAMA 283 (6): 779–782. doi:10.1001/jama.283.6.779. 
  10. ^ Brown, G., Vukovich, M., and King, D.:"Testosterone Prohormone Supplements", Medicine and Science in Sports and Exercise, 38(8):1451-1461.
  11. ^ Susman, E.J., et al. "Hormones, Emotional Dispositions, and Aggressive Attributes in Young Adolescents", Child Development, Vol. 58, No. 4, Aug 1987.[page needed]
  12. ^ a b Chen F, Knecht K, Leu C, et al. (August 2004). "Partial agonist/antagonist properties of androstenedione and 4-androsten-3beta,17beta-diol". The Journal of Steroid Biochemistry and Molecular Biology 91 (4-5): 247–57. doi:10.1016/j.jsbmb.2004.04.009. PMID 15336702. [non-primary source needed]
  13. ^ Broeder, CE; Quindry, J; Brittingham, K; Panton, L; Thomson, J; Appakondu, S; Breuel, K; Byrd, R et al. (2000). "The Andro Project: Physiological and hormonal influences of androstenedione supplementation in men 35 to 65 years old participating in a high-intensity resistance training program". Archives of Internal Medicine 160 (20): 3093–3104. doi:10.1001/archinte.160.20.3093. PMID 11074738. 
  14. ^ http://archinte.highwire.org/cgi/content/full/160/20/3093
  15. ^ http://www.pponline.co.uk/encyc/0907.htm