Utility of morphological abnormalities during early‐life development of the estuarine mummichog, Fundulus heteroclitus, as an indicator of estrogenic and antiestrogenic endocrine disruption

Abstract

To evaluate the use of morphological abnormalities for standard testing of endocrine-disrupting substances (EDS), we tested the hypothesis that developmental abnormalities are a sensitive indicator of exposure to waterborne estrogenic and antiestrogenic EDS during embryonic, larval, and juvenile stages in the common estuarine killifish, the mummichog (Pisces: Cyprinodontidae). Static exposures with daily renewal were carried out with 10 to 10,000 ng/L of the estrogen agonist 17alpha-ethynylestradiol (EE2) or antagonist ZM189,154 (ZM) for the first 25 or 60 d of life. Incidence of skeletal abnormalities (scoliosis, lordosis, head, craniofacial, jaw, fin) and soft tissue abnormality (anal swelling) were significantly increased by EE2 but only at high concentrations (1,000 or 10,000 ng/L). Sixty-day exposure produced more severe abnormalities than 25-d exposure and in a higher proportion of fish. Within the longer exposure, 10,000 ng/L EE2 produced more abnormal fish than 1,000 ng/L (100% vs 51.6%) and more abnormalities per abnormal fish (5.73 vs 1.47). Fish reared to 12 months in clean water after exposure for 60 d to 10,000 ng/L EE2 survived at a lower rate than controls, retained abnormalities with the exception of anal swelling and, like fish exposed to other concentrations of EE2 and ZM, showed increased weight at length at 6 and 12 months. Sixty-day exposure to ZM increased the incidence of scoliosis (1,000 ng/L) but decreased the overall incidences of abnormal fish and lordosis (10 and 10,000 ng/L). No impacts of EE2 or ZM were observed before hatch, and clearing and staining of larvae demonstrated that expression of vertebral abnormalities coincided temporally with ossification. We conclude that morphological abnormalities in mummichogs are not a sensitive indicator of exposure to estrogenic or antiestrogenic waterborne EDSs at environmentally relevant concentrations.

Estrogen receptor-related receptors in the killifish Fundulus heteroclitus: diversity, expression, and estrogen responsiveness

“…F. heteroclitus has been used as a model species for several recent studies of endocrine disruption. In particular, laboratory and natural populations exposed to environmental contaminants show altered levels of sex steroids (Dube & MacLatchy 2001, Hewitt et al 2002, MacLatchy et al 2003, Boudreau et al 2004, Greytak et al 2005, thyroid hormones (Zhou et al 2000, Carletta et al 2002, and aromatase mRNA (Greytak et al 2005). Given the cross-talk between mammalian ERs and ERRs (Vanacker et al 1999a, Giguere 2002, and the hypothesized regulatory role of ERRa in aromatase and thyroid receptor expression (Vanacker et al 1998, Yang et al 1998, elucidation of ERR signaling may provide insight into endocrine regulation and disruption in this model species.…”

Developmental exposures to waterborne abused drugs alter physiological function and larval locomotion in early life stages of medaka fish

“…The chorion (egg envelope) often has a barrier role in protecting fish embryos against exogenous substances or toxic ions (Boudreau et al, 2004). We demonstrated that embryonic exposure to environmentally relevant to micromolar levels of KET and MET delayed the heart rate and hatching time ( Figure 1) and increased the incidence of developmental abnormality (e.g., hemorrhage and defects in the eye and/or heart) ( Table S3, SI).…”

Fundulus as the premier teleost model in environmental biology: Opportunities for new insights using genomics

“…In both laboratory and field studies, killifish have been used to document effects of environmental chemicals on many different end-points of reproduction and development such as viability and fertilizability of eggs and sperm (Khan and Weis, 1987a), cytogenetic effects (Crawford and Guarino, 1976;Perry et al, 1988;Black et al, 1998a,b), embryo mortality, rate of development, developmental deformities, time to hatching and hatching success (Weis and Weis, 1974;Crawford and Guarino, 1976;Weis and Weis, 1977;Black et al, 1998a,b;Ownby et al, 2002;Boudreau et al, 2004;Wassenberg and Di Giulio, 2004b;Boudreau et al, 2005;Wassenberg et al, 2005;Gonzalez et al, 2006;Timme-Laragy et al, 2006), as well as larval growth, spontaneous activity, prey-capture ability, startle response, learning ability, neurotransmitter levels (Zhou et al, 1999;Zhou et al, 2001;Weis et al, 2003;Timme-Laragy et al, 2006) and sex ratios (Matta et al, 2001). End-points used to assess reproductive condition of sexually mature adults include reproductive success, circulating sex steroids, gonadal size, hepatic size, yolk protein synthesis, and genetic markers such as CYP19 aromatases, ER and vitellogenin (Black et al, 1998a,b;Monteverdi and Di Giulio, 2000;Matta et al, 2001;MacLatchy et al, 2003;Boudreau et al, 2004;Boudreau et al, 2005;Greytak et al, 2005;Greytak and Callard, 2007).…”

“…End-points used to assess reproductive condition of sexually mature adults include reproductive success, circulating sex steroids, gonadal size, hepatic size, yolk protein synthesis, and genetic markers such as CYP19 aromatases, ER and vitellogenin (Black et al, 1998a,b;Monteverdi and Di Giulio, 2000;Matta et al, 2001;MacLatchy et al, 2003;Boudreau et al, 2004;Boudreau et al, 2005;Greytak et al, 2005;Greytak and Callard, 2007).…”