Conversely, unlike DHEA, fluasterone has minimal or no androgenic or estrogenic activity, and due to the presence of the fluorine atom at the C16α position, its metabolism at the C17α position is sterically hindered and thus it cannot be metabolized into androgens like testosterone or estrogens like estradiol. Also in contrast to DHEA, fluasterone does not produce sedation or seizures in animals and hence is not thought to interact with the GABAA receptor. In addition, unlike DHEA, fluasterone has reduced or no effects as a peroxisome proliferator (i.e., lacks activity at the PPARαTooltip peroxisome proliferator-activated receptor alpha), and hence does not pose a risk of liver toxicities such as hepatomegaly or hepatocellular carcinoma. It is for these reasons that fluasterone was developed and was considered to be advantageous to DHEA.
Due to extensive first-passhepatic and/or gastrointestinal metabolism, very high doses of DHEA and fluasterone are necessary for effectiveness. In animals, the efficacy of fluasterone is increased 40-fold when administered parenterally, and for this reason, a non-oral formulation of fluasterone was selected for clinical development. However, the development of fluasterone was nonetheless stopped reportedly due to its low potency and low oral bioavailability, which are said to have rendered it unsuitable for clinical use.
References
↑"Fluasterone". AdisInsight. S pringer Nature Switzerland AG.
↑Auci D, Kaler L, Subramanian S, Huang Y, Frincke J, Reading C, Offner H (September 2007). "A new orally bioavailable synthetic androstene inhibits collagen-induced arthritis in the mouse: androstene hormones as regulators of regulatory T cells". Annals of the New York Academy of Sciences. 1110 (1): 630–640. Bibcode:2007NYASA1110..630A. doi:10.1196/annals.1423.066. PMID17911478. S2CID32258529.
↑Brown AP, Kirchner DL, Morrissey RL, Das SR, Fitzgerald RL, Crowell JA, Levine BS (2003). "Endocrine effects of dehydroepiandrosterone and its fluorinated analog, fluasterone, in rats". Drug Development Research. 58 (2): 169–178. doi:10.1002/ddr.10156. ISSN0272-4391. S2CID98206458.