Orteronel is an androgenbiosynthesisinhibitor. It selectively inhibits the enzyme CYP17A1[3] which is expressed in testicular, adrenal, and prostatic tumor tissues. CYP17 catalyzes two sequential reactions: (a) the conversion of pregnenolone and progesterone to their 17α-hydroxy derivatives by its 17α-hydroxylase activity, and (b) the subsequent formation of dehydroepiandrosterone (DHEA) and androstenedione, respectively, by its 17,20-lyase activity.[4] DHEA and androstenedione are androgens and precursors of testosterone. Inhibition of CYP17 activity thus decreases circulating levels of testosterone.
^Yamaoka, M; Hara, T; Hitaka, T; Kaku, T; Takeuchi, T; Takahashi, J; Asahi, S; Miki, H; et al. (2012). "Orteronel (TAK-700), a novel non-steroidal 17,20-lyase inhibitor: Effects on steroid synthesis in human and monkey adrenal cells and serum steroid levels in cynomolgus monkeys". The Journal of Steroid Biochemistry and Molecular Biology. 129 (3–5): 115–28. doi:10.1016/j.jsbmb.2012.01.001. PMID22249003. S2CID20204862.
^Attard G, Belldegrun AS, de Bono JS (December 2005). "Selective blockade of androgenic steroid synthesis by novel lyase inhibitors as a therapeutic strategy for treating metastatic prostate cancer". BJU Int. 96 (9): 1241–6. doi:10.1111/j.1464-410X.2005.05821.x. PMID16287438. S2CID36575315.