Estradiol‐17β and testosterone levels in the cockleFulvia muticaduring the annual reproductive cycle

Abstract

In this study, we investigated seasonal variations in the concentrations of estradiol-17β (E 2 ) and testosterone (T) in the gonad of the cockle Fulvia mutica from March 2004 to February 2005 in relation to the reproductive cycle. Histological data showed that F. mutica is a hermaphrodite bivalve species, and gametogenesis took place during winterspring (November-April) and spawning occurred in summer (May-June) when water temperature was higher. E 2 and T concentrations were measured by enzyme-linked immunosorbent assay (ELISA). E 2 concentrations varied between 7.27 and 32.63 pg/g wet weight and T concentrations ranged from 22.83 to 77.15 pg/g wet weight throughout the year. Both steroids exhibited a similar annual pattern that correlated with the reproductive cycle. The two peaks of E 2 and T concentrations in November and MayJune occurred at critical moments of the F mutica reproductive cycle: the onsets of gametogenesis and of the spawning period. E 2 andT concentrations were low during the non-reproductive period extending from July to October. These results suggest that E 2 and T could play a role as endogenous modulators in the reproductive cycle of F. mutica.

Variations of estradiol-17β and testosterone levels correlated with gametogenesis in the gonad of Zhikong scallop (Chlamys farreri) during annual reproductive cycle

“…Similar profiles have been reported in several bivalves (Matsumoto et al 1997;Osada et al 2004b;Gauthier-Clerc et al 2006a;Liu et al 2008;Yan et al 2011;Ni et al 2013). E2 can potentiate the effect of serotonin (5-hydroxytryptamine; 5-HT), which induces egg release from small blocks of P. yessoensis (Osada et al 1992).…”

“…Marked differences were observed when we compared steroid concentrations of different bivalves (De Longcamp et al 1974;Matsumoto et al 1997;Siah et al 2002;Osada et al 2004b;Gauthier-Clerc et al 2006a;Liu et al 2008;Yan et al 2011;Ni et al 2013). The differences are related to variability between species, gonadal development status, extraction procedures, and quantification methods (Gauthier-Clerc et al 2006a).…”

“…Steroids, such as estradiol-17␤ (E2), testosterone (T), and progesterone (P), have been reported in many bivalves (De Longcamp et al 1974;Matsumoto et al 1997;Reis-Henriques and Coimbra 1990;ReisHenriques et al 1990;Siah et al 2002;Zhu et al 2003;Janer et al 2005;Lavado et al 2006;Mouneyrac et al 2008;Negrato et al 2008;Dévier et al 2010). Although steroid concentrations in bivalves are significantly different from each other, variations in steroids have been shown to be correlated with the reproductive cycle (Gauthier-Clerc et al 2006a;Ketata et al 2007;Liu et al 2008;Yan et al 2011;Ni et al 2013). The roles of steroids in reproduction also have been investigated in bivalves for years.…”

Profile of 17ß-estradiol, vitellogenin, and egg diameter during gonad maturation process of striped catfish Pangasianodon hypophthalmus

“…In the recent years, the reproductive biology of many fish species have been studied by analyzing the vitellogenin (Vtg) and 17ß-estradiol (E2) levels in the blood plasma (Muhammad et al, 2011;Tirado et al, 2017;Luck et al, 2019). Variations in steroids have been shown to be correlated with the reproductive cycle (Liu et al, 2008;Yan et al, 2011;Ni et al, 2013).…”

Peer Review #2 of "Aromatisation of steroids in the bivalve Mytilus trossulus (v0.1)"

“…Hence, Scott (Scott, 2013) in a critical review concluded that there is no indisputable bioassay evidence that vertebrate sex steroids have endocrinological or reproductive roles in molluscs. In spite of that, an association between gametogenesis stage and steroid content was reported with maximal steroids concentration often observed during reproduction peak and minimal concentration during low stage of gametogenesis (Jianbin, 2013;Wang & Croll, 2007;Liu, Li & Kong, 2008;Ciocan et al, 2010;Morthorst et al, 2014;Hallmann et al, 2016). In M. trossulus from the Gulf of Gdańsk (Baltic Sea, Poland), seasonal differences in E2 and T concentrations in gonads and gills were also found, but no direct relation between steroids level and stage of gonad development was confirmed (Zabrzańska et al, 2015;Hallmann et al, 2016;Smolarz et al, 2018).…”