Effects of 4-nonylphenol and 17alpha-ethynylestradiol exposure in the Sydney rock oyster, Saccostrea glomerata: Vitellogenin induction and gonadal development.
Adult Saccostrea glomerata were exposed to environmentally relevant concentrations of 4-nonylphenol (1microg/L and 100microg/L) and 17alpha-ethynylestradiol (5ng/L and 50ng/L) in seawater over 8 weeks. Exposures were performed to assess effects on vitellogenin induction and gonadal development during reproductive conditioning. Chronic direct estrogenicity within gonadal tissue was assessed via an estrogen receptor-mediated, chemical-activated luciferase reporter gene-expression assay (ER-CALUX). Estradiol equivalents (EEQ) were greatest in the 100microg/L 4-nonylphenol exposure (28.7+/-2.3ng/g tissue EEQ) while 17alpha-ethynylestradiol at concentrations of 50ng/L were 2.2+/-1.5ng/g tissue EEQ. Results suggest 4-nonylphenol may be accumulated in tissue and is partly resistant to biotransformation; maintaining its potential for chronic estrogenic action, while 17alpha-ethynylestradiol, although exhibiting greater estrogenic potency on biological endpoints possibly exerts its estrogenic action before being rapidly metabolised and/or excreted. A novel methodology was developed to assess vitellogenin using high-performance liquid chromatography (HPLC). Exposure to both 17alpha-ethynylestradiol (50ng/L) and 4-nonylphenol (100microg/L) produced increases in vitellogenin for females, whereas males exhibited increases in vitellogenin when exposed to 50ng/L 17alpha-ethynylestradiol only. Females exhibited greater vitellogenin responses than males at 50ng/L 17alpha-ethynylestradiol only. Histological examination of gonads revealed a number of individuals exhibiting intersex (ovotestis) in 50ng/L 17alpha-ethynylestradiol exposures. Male individuals in 1microg/L and 100microg/L 4-nonylphenol exposures and 5ng/L 17alpha-ethynylestradiol were at earlier stages of spermatogenic development than corresponding controls.
Andrew
M N
MN
School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia. Megan.Andrew@newcastle.edu.au
Dunstan
R H
RH
O'Connor
W A
WA
Van Zwieten
L
L
Nixon
B
B
MacFarlane
G R
GR
D000818:Animals; D012734:Disorders of Sex Development; D004997:Ethinyl Estradiol / Q000633:toxicity*; D005260:Female; D006066:Gonads / Q000187:drug effects*; D008297:Male; D010125:Ostreidae / Q000187:drug effects* / Q000254:growth & development; D010053:Ovary / Q000187:drug effects; D010636:Phenols / Q000633:toxicity*; D012744:Sex Ratio; D013737:Testis / Q000187:drug effects; D014818:Vitellogenesis / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D010636:Phenols; D014874:Water Pollutants, Chemical; D004997:Ethinyl Estradiol; C041594:4-nonylphenol