Synthesis of 17,20β,21‐trihydroxypregn‐4‐en‐3‐one by ovaries of reproductively mature Atlantic cod Gadus morhua

• Published in: Journal of Fish Biology
• Main Authors: Tveiten, H., Frantzen, M., Scott, A. M., Scott, A. P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2010
• Subjects: atlantic cod; Gadus morhua
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.2010.02655.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.2010.02655.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.2010.02655.x

Atlantic cod Gadus morhua ovaries were incubated in vitro with tritiated 17‐hydroxypregn‐4‐ene‐3,20‐dione (17‐P) to determine whether 17,20β‐dihydroxypregn‐4‐en‐3‐one (17,20β‐P) or 17,20β, 21‐trihydroxypregn‐4‐en‐3‐one (17,20β,21‐P), or both, were more likely to be the steroid responsible for inducing oocyte final maturation ( i.e. resumption of meiosis). Only 17,20β,21‐P was produced, in addition to 11‐deoxycortisol (17,21‐P), which is intermediate between 17‐P and 17,20β,21‐P. Also, the 5β‐reduced forms of 17‐P, 17,21‐P and 17,20β,21‐P were all found. Some sulphation of 21‐hydroxylated steroids was demonstrated. The ability of female G. morhua to make 17,20β,21‐P but not 17,20β‐P was confirmed by radioimmunoassay of plasma samples from spawning fish. Although small amounts of 17,20β‐P immunoreactivity were detected in a few plasma samples, this was shown, by thin‐layer chromatography, to be mostly due to cross‐reaction with other unidentified compounds. The evidence strongly suggests that 17,20β,21‐P is more likely than 17,20β‐P to be the maturation‐inducing steroid in G. morhua .