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Impacts Of Environmental Stressors On Mummichog (Fundulus Heteroclitus) Growth And The Gh-Igf1 Pathway Using A Laboratory Bioassay, Olena Kuntyj
Theses and Dissertations (Comprehensive)
Using a flow-through laboratory bioassay, experiments investigated the effects of limited feeding, increased temperature, ammonium chloride (NH4Cl), and 17α-ethinylestradiol (EE2) on juvenile mummichog (Fundulus heteroclitus) growth. Weight measurements were taken every three days as the apical growth endpoint. Gene expression was examined by qPCR for genes in the GH (growth hormone)-IGF1 (insulin-like growth factor 1) pathway, including gh, igf1, and their receptors (ghra, ghrb, igf1ra, igf1rb). In Experiment 1, juvenile mummichog were exposed to excess or limited feed for 21 days. The limited-fed mummichog weighed less, were …
Molecular Characterization Of The Mummichog (Fundulus Heteroclitus) Ovarian Steroidogenic Pathway And Implications For Exogenous Estrogen Effects During Follicular Development, Thiviya Kanagasabesan
Molecular Characterization Of The Mummichog (Fundulus Heteroclitus) Ovarian Steroidogenic Pathway And Implications For Exogenous Estrogen Effects During Follicular Development, Thiviya Kanagasabesan
Theses and Dissertations (Comprehensive)
This study investigated ovarian development in Fundulus heteroclitus (mummichog), through molecular characterization of key mediators in the ovarian steroidogenic pathway; these included ovarian StAR (steroidogenic acute regulatory protein), cytochrome P450 enzymes, estrogen receptors (ERα, ERβ1 and ERβ2), and gonadotropin receptors (FSHr and LHr); additionally, hepatic vitellogenin (VTG1) and ERs, and brain P450 aromatase (P450arom; CYP19b) were studied. Fish were staged into cortical alveolus, vitellogenic, early mature, late mature, and ovulating stages of maturation; blood (plasma), ovary (tissue and isolated ovarian follicles per stage), liver, and brains were collected. Testosterone (T), 17β-estradiol (E2) and maturation inducing steroid (MIS), measured …
The Effects Of 17Α-Ethynylestradiol (Ee2) On Gonadal Development And Differentiation In The Estuarine Killifish, Fundulus Heteroclitus, Ibrahim Chehade
The Effects Of 17Α-Ethynylestradiol (Ee2) On Gonadal Development And Differentiation In The Estuarine Killifish, Fundulus Heteroclitus, Ibrahim Chehade
Theses and Dissertations (Comprehensive)
Endocrine disrupting substances (EDSs) comprise a wide variety of chemicals that perturb normal endocrine function including developmental and reproductive processes in vertebrates. The synthetic estrogen 17α-ethynylestradiol (EE2) is a commonly-used model EDS because of its environmental relevance and its effects on the reproductive endocrine system. Early life-stage exposure of fish to estrogenic EDSs causes effects such as intersex (ovotestes in males) and feminization. This study aims to confirm the period of gonadal differentiation in the estuarine killifish or mummichog (Fundulus heteroclitus) and to determine the sensitivity of gonadal development to EE2. Artificially-regressed mummichog were spawned, and …
Effects Of 17Α-Ethinylestradiol (Ee2) On Reproductive Endocrine Status In Mummichog (Fundulus Heteroclitus) Under Differing Salinity And Temperature Conditions, Esteban Gillio Meina
Effects Of 17Α-Ethinylestradiol (Ee2) On Reproductive Endocrine Status In Mummichog (Fundulus Heteroclitus) Under Differing Salinity And Temperature Conditions, Esteban Gillio Meina
Theses and Dissertations (Comprehensive)
Waterborne exposure to 17α-ethinylestradiol (EE2), a synthetic estrogen, has previously been shown to decrease reproductive endocrine status in the estuarine killifish or mummichog (Fundulus heteroclitus macrolepidotus; northern subspecies). To evaluate if variations in salinity or temperature holding conditions modify the effects of EE2 on gonad size, plasma reproductive steroid levels, and gonadal steroidogenesis, mummichog were exposed in vivo for 14 days to 0, 50 and 250 ng/L EE2 in 0, 16 and 32 ppt salinity at 18°C and to 0 and 250 ng/L EE2 at 10, 18 and 26°C at 16 ppt salinity. …