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ERIC Number: EJ855044
Record Type: Journal
Publication Date: 2007
Pages: 4
Abstractor: As Provided
Reference Count: 16
ISBN: N/A
ISSN: ISSN-1084-6522
Inverse Effects on Growth and Development Rates by Means of Endocrine Disruptors in African Clawed Frog Tadpoles ("Xenopus Laevis")
Hackney, Zachary Carl
NCSSSMST Journal, v12 n2 p8-11 Spr 2007
Previous work on fish, frogs, and salamanders, showed the ability for estrogen (EE2) and anthropogenic endocrine disruptors to skew sex ratios and cause hermaphrodism. This study addressed the effects of estrogens on growth and development rates of African clawed frog tadpoles ("Xenopus laevis") during their gender determination stages. The effects of estrogen mimics (EM2) have never been studied side-by-side with EE2; I investigated the effects of estradiol [beta]-17 (EE2) and ethynylestradiol [alpha]-17 (EM2). Tadpoles were kept individually in containers filled with either EE2 (100 ng/ml), EM2 (100 ng/ml), or dH[subscript 2]O control. Stage transitions and body sizes were monitored daily over three weeks. Results showed EE2 and EM2 caused faster development rates relative to the control (p less than 0.001) and slower growth rates relative to the control (p less than 0.005). While there were no detectable differences between EE2 and EM2 development rates, the growth rate in the mimic treatment was significantly slower than the growth rate in the EE2 treatment (p less than 0.001). The inverse correlation between development rate and growth rate has implications for the onset of sexual maturity and fecundity. The difference in the growth rates between EE2 and EM2 may be explained by the higher binding affinity of the mimic, which in turn causes the mimic to stay in the body longer than EE2 and may exacerbate the effect on growth rate. How this affects populations of amphibians needs to be explored further. (Contains 2 figures.)
National Consortium for Specialized Secondary Schools of Mathematics, Science and Technology. 3020 Wards Ferry Road, Lynchburg, VA 24502. Tel: 434-582-1104; Fax: 434-239-4140; e-mail: office@ncsssmst.org; Web site: http://www.ncsssmst.org
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A