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Please use this identifier to cite or link to this item:
http://hdl.handle.net/10225/147
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| Title: | CLONING AND EXPRESSION OF KEY ENDOCRINE GENES IN A STUDY ON ESTROGEN STIMULATED SEXUAL SIZE DIMORPHISM (SSD) IN YELLOW PERCH |
| Authors: | Lynn, Scott George |
| Keywords: | estrogen
growth
gene expression
yellow perch
sex |
| Date Created: | 2006 |
| Publisher: | University of Kentucky |
| Abstract: | Yellow perch (Perca flavescens) exhibit an estrogen stimulated sexual size
dimorphism (SSD) wherein females grow faster and larger than males. In an effort to
gain better understanding of this phenomenon, several genes associated with sexual
development, reproduction and growth were cloned, including prolactin (PRL),
somatolactin (SL), insulin-like growth factor-I (IGF-Ib), the estrogen receptors (ERα and
ERβa) and ovarian aromatase (CYP19A1). Real-time quantitative PCR (qPCR) assays
for all the genes listed above, plus growth hormone (GH), were developed to measure
mRNA levels in pituitary, liver and ovary.
Adult fish were collected from Lake Erie in the spring (May) and autumn
(October) over two years and tissue mRNA levels, body weight, age, gonadasomatic
index (GSI) and hepatasomatic index (HSI) were determined. Sex-specific differences
included females having higher body weights, HSI and liver ERα mRNA levels than
males and males having higher liver ERβa and liver CYP19A1 mRNA levels than
females. Season had a significant effect on growth factors (GH and IGF-Ib), with higher
mRNA levels in spring, which corresponded with higher liver CYP19A1 mRNA levels.
Ovary CYP19A1 mRNA levels, which were higher in autumn, had a significant negative
correlation with GH and IGF-Ib mRNA levels and liver ERβa mRNA levels had a
significant positive correlation with IGF-Ib mRNA levels.
A brood of juvenile yellow perch was sampled through the first year of
development up to 421 days post-hatching (dph). There was a significant effect of dph
on body weight, GH, PRL, SL, IGF-Ib, liver ERα, liver ERβa and ovary CYP19A1
mRNA levels. Only liver ERβa mRNA had a significant effect of sex and exhibited
significant differences between males and females at 379 and 421 days post-hatching
(dph). This work on yellow perch can provide predictive capabilities for estrogendependent
physiological processes in other species, especially teleosts, and can also make
yellow perch an exciting option for future ecotoxicogenomic studies. |
| URI: | http://hdl.handle.net/10225/147 |
| Appears in Collections: | Electronic Theses and Dissertations
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| dissertation.pdf | | 2559Kb | Adobe PDF | View/Open |
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