Proposed Abstract Title

Wastewater treatment plant effluent alters pituitary gonadotropin mRNA levels in juvenile coho salmon (Oncorhynchus kisutch)

Type of Presentation

Oral

Session Title

Contaminants of Emerging Concern: Intersection of Occurrence, Impacts, Research, and Policy

Location

2016SSEC

Description

Endocrine disrupting compounds (EDCs), including natural and synthetic estrogens present in wastewater treatment plant (WWTP) effluents can interfere with reproduction in fish and induce hepatic vitellogenin (vtg) in juveniles or adult males. The pituitary gland is a central regulator of reproduction, producing follicle-stimulating hormone (FSH) and luteinizing hormone (LH) that regulate gonadal sex steroid synthesis and gametogenesis. In turn, estrogens and androgens feedback and regulate FSH and LH. However, effects of EDCs on the pituitary gland have not been extensively investigated. Our aim was to examine effects of WWTP effluent on hepatic vtg and pituitary LH and FSH beta subunits (lhb, fshb) mRNAs in juvenile coho salmon. First, a controlled 72-hr exposure to 17α-ethynylestradiol (EE2, a synthetic estrogen in oral contraceptives) and trenbolone (TREN, a synthetic androgen used in livestock production) was performed. Second, fish were exposed to 0, 20 or 100% WWTP effluents for 72 hrs. Lhb mRNA levels were significantly increased in response to 2.5 or 12 ng EE2/L, and to 5 WWTP effluents. Transcript levels of vtg were dramatically increased in response to 12 ng EE2/L, but not to 2.5 ng EE2/L, TREN or any WWTP effluents. Mean levels of natural and synthetic estrogens in bile were higher in fish with elevated pituitary lhb expression, suggesting that the observed lhb induction may be due to estrogenic activity of WWTP effluents. These results suggest that lhb gene expression may be a more sensitive index of exposure to estrogenic chemicals than hepatic vtg under short-term exposure studies with juvenile coho salmon. Further work is needed to evaluate the utility of lhb induction as a potential indicator of estrogen exposure in immature salmon. This work was supported by the National Oceanic and Atmospheric Administration and US Environmental Protection Agency, Region 10.

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Wastewater treatment plant effluent alters pituitary gonadotropin mRNA levels in juvenile coho salmon (Oncorhynchus kisutch)

2016SSEC

Endocrine disrupting compounds (EDCs), including natural and synthetic estrogens present in wastewater treatment plant (WWTP) effluents can interfere with reproduction in fish and induce hepatic vitellogenin (vtg) in juveniles or adult males. The pituitary gland is a central regulator of reproduction, producing follicle-stimulating hormone (FSH) and luteinizing hormone (LH) that regulate gonadal sex steroid synthesis and gametogenesis. In turn, estrogens and androgens feedback and regulate FSH and LH. However, effects of EDCs on the pituitary gland have not been extensively investigated. Our aim was to examine effects of WWTP effluent on hepatic vtg and pituitary LH and FSH beta subunits (lhb, fshb) mRNAs in juvenile coho salmon. First, a controlled 72-hr exposure to 17α-ethynylestradiol (EE2, a synthetic estrogen in oral contraceptives) and trenbolone (TREN, a synthetic androgen used in livestock production) was performed. Second, fish were exposed to 0, 20 or 100% WWTP effluents for 72 hrs. Lhb mRNA levels were significantly increased in response to 2.5 or 12 ng EE2/L, and to 5 WWTP effluents. Transcript levels of vtg were dramatically increased in response to 12 ng EE2/L, but not to 2.5 ng EE2/L, TREN or any WWTP effluents. Mean levels of natural and synthetic estrogens in bile were higher in fish with elevated pituitary lhb expression, suggesting that the observed lhb induction may be due to estrogenic activity of WWTP effluents. These results suggest that lhb gene expression may be a more sensitive index of exposure to estrogenic chemicals than hepatic vtg under short-term exposure studies with juvenile coho salmon. Further work is needed to evaluate the utility of lhb induction as a potential indicator of estrogen exposure in immature salmon. This work was supported by the National Oceanic and Atmospheric Administration and US Environmental Protection Agency, Region 10.