Neurosteroid activity
DHT, via its metabolite 3α-androstanediol (produced by 3α-hydroxysteroid dehydrogenase (3α-HSD)), is a neurosteroid that acts via positive allosteric modulation of the GABAA receptor. Testosterone, via conversion into DHT, also produces 3α-androstanediol as a metabolite and hence has similar activity. Some AAS that are or can be 5α-reduced, including testosterone, DHT, stanozolol, and methyltestosterone, among many others, can or may modulate the GABAA receptor, and this may contribute as an alternative or additional mechanism to their central nervous system effects in terms of mood, anxiety, aggression, and sex drive. Chemistry
AAS are androstane or estrane steroids. They include testosterone (androst-4-en-17β-ol-3-one) and derivatives with various structural modifications such as:
17α-Alkylation: methyltestosterone, metandienone, fluoxymesterone, oxandrolone, oxymetholone, stanozolol, norethandrolone, ethylestrenol
19-Demethylation: nandrolone, trenbolone, norethandrolone, ethylestrenol, trestolone, dimethandrolone
5α-Reduction: androstanolone, drostanolone, mestanolone, mesterolone, metenolone, oxandrolone, oxymetholone, stanozolol
3β- and/or 17β-esterification: testosterone enanthate, nandrolone decanoate, drostanolone propionate, boldenone undecylenate, trenbolone acetateAs well as others such as 1-dehydrogenation (e.g., metandienone, boldenone), 1-substitution (e.g., mesterolone, metenolone), 2-substitution (e.g., drostanolone, oxymetholone, stanozolol), 4-substitution (e.g., clostebol, oxabolone), and various other modifications. Detection in body fluids
The most commonly employed human physiological specimen for detecting AAS usage is urine, although both blood and hair have been investigated for this purpose. The AAS, whether of endogenous or exogenous origin, are subject to extensive hepatic biotransformation by a variety of enzymatic pathways. The primary urinary metabolites may be detectable for up to 30 days after the last use, depending on the specific agent, dose and route of administration.
Leeches can reduce swelling in the tissues and promote healing, helping in particular to restore circulation after microsurgery to reattach body parts. Other clinical applications include varicose veins, muscle cramps, thrombophlebitis, and joint diseases such as epicondylitis and osteoarthritis.Leech secretions contain several bioactive substances with anti-inflammatory, anticoagulant and antimicrobial effects. One active component of leech saliva is a small protein, hirudin. It is widely used as an anticoagulant drug to treat blood-clotting disorders, and manufactured by recombinant DNA technology.In 2012 and 2018, Ida Schnell and colleagues trialled the use of Haemadipsa leeches to gather data on the biodiversity of their mammalian hosts in the tropical rainforest of Vietnam, where it is hard to obtain reliable data on rare and cryptic mammals. They showed that mammal mitochondrial DNA, amplified by the polymerase chain reaction, can be identified from a leechs blood meal for at least four months after feeding. They detected Annamite striped rabbit, small-toothed ferret-badger, Truong Son muntjac, and serow in this way. Water pollution
Exposure to synthetic estrogen as used in contraceptive medicines, which may enter freshwater ecosystems from municipal wastewater, can affect leeches reproductive systems. Although not as sensitive to these compounds as fish, leeches showed physiological changes after exposure, including longer sperm sacs and vaginal bulbs, and decreased epididymis weight. Notes
References
General bibliography
Ruppert, Edward E.; Fox, Richard S.; Barnes, Robert D. (2004). Invertebrate Zoology, 7th Edition. Cengage Learning. ISBN 978-81-315-0104-7. External links
 Media related to Hirudinea at Wikimedia Commons
 Data related to Hirudinea at Wikispecies
 The dictionary definition of leech at Wiktionary