Estrogenicity of 4-nonylphenol and diethylstilbestrol on in vitro oocyte maturation of the dusky tripletooth goby,Tridentiger obscurus

Abstract

This study investigated the estrogenicity of 4-nonylphenol (NP) and diethylstilbestrol (DES) in vitro during oocyte maturation in the marine fish, Tridentiger obscurus, using steroid hormone assays and GVBD assay. Vitellogenic (0.53 mm diameter) and fully vitellogenic (0.75 mm diameter) oocytes were in vitro exposed to NP (0.045Á453.82 nM) and DES (0.037Á372.62 nM). In vitellogenic oocytes, 45.38 and 453.82 nM NP and 3.73Á372.62 nM DES increased the estradiol-17b (E2)/testosterone (T) ratio. In fully vitellogenic oocytes, 0.45, 45.38 and 453.82 nM NP and 3.73 nM DES increased E2/T. In the GVBD assay, 0.45 and 4.54 nM NP and 0.037, 3.73 and 37.26 nM DES inhibited GVBD. These results suggest that NP and DES have estrogen-agonistic effects in oocyte maturation in T. obscurus. In addition, NP and DES have different sensitivity according to the oocyte developmental stage, and the estrogenagonistic effects of DES were greater than were those of NP.

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“…Hwang, Lee, Kim and Baek, 2008 and Hwang Kima, Kima, Leeb and Baeka 2010, demonstrated the estrogenic potency of 4-NP during in vitro oocyte maturation in dusky triple tooth goby Tridentiger obscures and greenling Hexagrammos otakii which showed increased E2/T ratio. In the assay, these workers found that 4-NP inhibited GVBD in fully vitellogenic oocytes at concentrations of 0.45 and 4.54 nM, similar to DES at concentrations of 0.037, 3.73 and 37.26 nM (Hwang, Lee, Kim & Baek, 2008;Hwang Kima, Kima, Leeb & Baeka 2010). The GVBD inhibition was attributed to the estrogen agonistic action of 4-NP.…”

“…Many pesticides, including PCBs adversely affect this process in farm animals (Pocar, Brevini, Fischer, & Gandolfi, 2003). Studies in fishes with EDCs showed that these chemicals produced agonistic or antagonistic effects on oocyte maturation (Hwang Kima, Kima, Leeb & Baeka 2010;Tokumoto, Tokumoto & Horiguchi, 2005;Tokumoto, Tokumoto & Thomas, 2007;Hwang, Lee, Kim & Baek, 2008). We tested the effect of 4-NP on GVBD, an indicator of meiotic maturation.…”

“…In catfish, the low concentrations (0.1, 0.5 ng/mL) stimulated E2, but high concentrations (1.0, 10, 50, 100 and 200 ng/mL) unchanged or decreased E2 levels at both 12 and 24 h. Testosterone levels were increased at 0.1, 0.5, 1.0 ng/mL concentrations, but decreased at 50, 100 and 200 ng/mL concentrations. The E2/T ratio is considered a reliable index to assess endocrine disruption (Hwang Kima, Kima, Leeb & Baeka 2010;Folmar et al, 2000;Labadie & Budzinski, 2006). Both BPA and p-NP lowered the ratio of androgens to estrogens in juvenile turbots (Labadie & Budzinski, 2006),but acted differently; p-NP decreased androstenedione and 11-KT levels, while BPA elevated estrone level.…”

“…They reported that 4-NP increased endogenous E2 production at the vitellogenic stage and inhibited GVBD at the fully vitellogenic stage. In fish, exposure to DES led to increase in vitellogenin level and inhibited GVBD, and the estrogen agonist effect of DES was more as compared to NP (Zhong et al, 2005;Hwang Kima, Kima, Leeb & Baeka 2010). Tokumoto, Tokumoto, Horiguchi, Ishikawa and Nagahama (2004) demonstrated that DES induced oocyte maturation in a manner similar to MIS.…”

“…In adult fish, exposure to xenoestrogens such as diethylstilbestrol (DES) and bisphenol A (BPA) has been reported to cause increased or decreased vitellogenin production in both male and female fish and inhibited FOM (Scholz & Gutzeit, 2000;Sohoni et al, 2001;Jobling & Tyler, 2003). Hwang, Kima, Kima, Leeb and Baeka (2010) reported that 4-NP elicited estrogen-agonistic effects on the development and maturation of Tridentiger obscures oocytes in vitro. They reported that 4-NP increased endogenous E2 production at the vitellogenic stage and inhibited GVBD at the fully vitellogenic stage.…”