Induction and Recovery of Estrogenic Effects After Short-Term 17β-Estradiol Exposure in Juvenile Rainbow Trout (Oncorhynchus mykiss)

Abstract

Estrogenic compounds found in the aquatic environment include natural and synthetic estrogen hormones as well as other less potent estrogenic xenobiotics. In this study, a comprehensive approach was used to examine effects on fish endocrine system endpoints during a short-term xenoestrogen exposure as well as after post-exposure recovery. Rainbow trout (Oncorhynchus mykiss) were exposed to an aqueous 17β-estradiol (E2) concentration of 0.473 μg l(-1) for 2 and 7 days (d) followed by a 14-d recovery period. At d2 and d7, plasma E2 concentrations in treated fish were 458- and 205-fold higher than in control fish and 23- and 16-fold higher than the exposure water concentration. E2 treatment resulted in significant increases in hepatosomatic index (HSI), plasma vitellogenin (VTG) protein concentrations, and liver VTG and estrogen receptor alpha mRNA levels. All of these parameters, with the exception of plasma VTG protein, returned to baseline values during the recovery period. Plasma cortisol concentrations were unaffected by treatment. This research shows varied time frames of the estrogen-responsive molecular-, biochemical-, and tissue-level alterations, as well as their persistence, in juvenile rainbow trout treated with aqueous E2. These results have implications for feral rainbow trout exposed to xenoestrogens and indicate the importance of evaluating a comprehensive suite of endpoints in assessing the impact of this type of environmental contaminant.

Altered burst swimming in rainbow trout Oncorhynchus mykiss exposed to natural and synthetic oestrogens

“…In fishes, plasma cortisol concentrations in the 30 to 300 ng ml −1 range are typically found in response to acute stressors (Barton, ). The highest cortisol concentration was found in the E2‐exposed group (34·5 ng ml −1 ); however, this was not a significant increase, results similar to other experiments with exposures of fishes to E2 (Fuzzen et al , ; Osachoff et al , ). Cortisol concentrations in net‐chased fish from the +ve CON group were significantly elevated [53·5 ng ml −1 ; Fig.…”

Effects of Water Temperature on Gonad Development in the Cold-Water Fish, Kumgang Fat Minnow <i>Rhynchocypris kumgangensis</i>

“…HSI has been shown to be affected by the levels of various hormones, including E2 and insulin-like growth factor-1 (IGF-1). Since E2 treatment has been found to increase HSI and vitellogenin synthesis in numerous fish species (Osachoff et al 2013, Pandelides et al 2014, Park et al 2010) and elevated water temperatures impair E2 secretion (King et al 2003), we speculate that the elevated water temperature might have attenuated E2 secretion in our system, leading to the observed reductions in HSI. Long-term exposure to warm temperatures was previously shown to decrease IGF-1 levels, HSI values, and growth among juveniles of the southern flounder, Paralichthys lethostigma (Luckenbach et al 2007).…”

2, 4-Dichloro-6-nitrophenol, a photonitration product of 2, 4-dichlorophenol, caused anti-androgenic potency in Chinese rare minnows (Gobiocypris rarus)

“…However, endocrine disrupters, such as nitrophenol, nonylphenol, octylphenol and BPA, also have been shown to induce nuclear receptor transcription (Osachoff et al, 2013;Qiu et al, 2013). Futhermore, these changes of ER/AR mRNA expression could result in reproductive and developmental toxicity (Ma et al, 2012;Nose et al, 2009).…”