Plasma concentrations of ovarian steroids in relation to oocyte final maturation and ovulation in female plaice sampled at sea

Abstract

Blood plasma concentrations of free 17 -oestradiol, free testosterone and glucuronidated testosterone were strongly positively related to the percentage of vitellogenic oocytes remaining in the ovaries of plaice Pleuronectes platessa caught at sea-being at their highest in pre-spawning (stage IV) females (i.e. those in which the oocytes were close to fully grown, but had not yet entered the stage of final maturation). In contrast, the concentrations of free and sulphated 17,20 -P, 3 ,17,20 -P-5 , and 3 ,17,21-P-5 were at their lowest in stage IV females. Free 17,20 -P (the putative maturation-inducing steroid) became only slightly elevated (less than twofold) during spawning (i.e. in stage V and VI females with hydrated and/or ovulated eggs). Sulphated 17,20 -P and 3 ,17,21-P-5 became slightly more elevated (three-to fourfold). However, sulphated 3 ,17,20 -P-5 concentrations increased 30-fold and were at their highest in fish in which only 40% of vitellogenic oocytes remained in the ovaries. Sulphated 17,20 -P, 3 ,17,20 -P-5 and 3 ,17,21-P-5 concentrations were significantly positively related to hyaline oocyte batch size; and sulphated 17,20 -P and sulphated 3 ,17,20 -P-5 were significantly negatively related to the degree of hydration of the hyaline oocytes. None of the steroid concentrations, however, was related to the time of capture. More ovulated females were found in the afternoon than at any other time of the day. 1998 The Fisheries Society of the British Isles

Physiological influences can outweigh environmental signals in otolith microchemistry research

“…Similar patterns were observed by Kalish (1991) and are corroborated by seasonal trends in ovary Ca and Sr concentrations in rainbow trout (Shearer 1984). In mature females, the period of hypercalcaemia is accompanied by synthesis of proteins and steroids specific to oocyte production and maturation (Scott et al 1998). Differences in their binding capacity and specificity may explain the sex-specific interactions observed for Sr B , Ca B and Pb B and may, in turn, affect ion availability to the otolith.…”

Fatty acid and proximate composition of wild male and female king angelfish (Holacanthus passer) gonads during the ripe and spent developmental stages

“…This steroid hormone induces the biosynthesis of vitellogenin in the liver of mature female fish, which is subsequently incorporated into the developing oocyte (Collier et al, 2003;Swanson et al, 2003;Guerriero, 2007). A correspondence between plasma concentration of E2 and the size or weight of the gonads has been established (Aruke and Goksoyr, 2003;Moncaut et al, 2003;Berg et al, 2004), therefore, it is considered as an indicator of female gonadal maturation or final oocyte maturation in female fish (Scott et al, 1998;Kokokiris et al, 2000).…”

Induccion del desove y espermiacion de anchoveta peruana Engraulis ringens (Jennyns, 1842) en cautiverio mediante la inyeccion de un analogo de GnRH

“…Sin embargo, en algunas especies se reporta al 17α,20ß,21-trihidroxi-4-pregnen-3-ona (17,20ß,21P) como el responsable de esta función (Patiño & Thomas, 1990;García et al, 2004;Alberro et al, 2008), lo cual podría estar sucediendo también en engráulidos. No debería descartarse tampoco la ocurrencia de acciones paracrinas o metabolizaciones de la 17,20ßP a nivel ovárico, las cuales pudiesen haber enmascarado sus fluctuaciones plasmáticas, tal como se ha descrito en otras especies (Scott & Canario, 1987;Scott et al, 1998;Asturiano et al, 2002). En este sentido, son necesarios más estudios para identificar al MIS en esta especie y la función que cumpliría el 17,20ßP para optimizar los desoves en cautiverio.…”