Effects of 17α-trenbolone and melengestrol acetate on Xenopus laevis growth, development, and survival.
The synthetic growth-promoting hormones trenbolone and melengestrol acetate have been detected in the environment near beef cattle feedlots and are reportedly transported via wind-borne particulate matter. Therefore, movement of synthetic hormones from beef cattle feedlots to water bodies via particulate matter is possible. Our objective was to evaluate potential effects of 17α-trenbolone (17α-TB), melengestrol acetate (MGA), and combinations of both on growth, development, and survival of Xenopus laevis larvae. On post-hatch day 2 (stage 33/34), X. laevis larvae were exposed to three nominal concentrations of 17α-TB (10, 100, and 500 ng/L), MGA (1, 10, and 100 ng/L), a combination of both (1/10, 10/100, and 100/500 ng/L MGA/17α-TB), frog embryo teratogenesis assay-Xenopus medium, or a solvent control. Significant increases in all X. laevis growth metrics were observed among larvae in the 1 ng/L MGA + 10 ng/L 17α-TB and 10 ng/L MGA + 100 ng/L 17α-TB treatments. Stage of development was increased among larvae in the 1 ng/L MGA + 10 ng/L 17α-TB treatment group and significantly decreased among those in the 500 ng/L 17α-TB treatment. Total body mass and snout-vent length of X. laevis larvae were significantly reduced in the 100 ng/L MGA and 100 ng/L MGA + 500 ng/L 17α-TB treatment groups. Larvae exposed to 500 ng/L 17α-TB had decreased total body mass, snout-vent length, and total length. In general, growth measurements decreased with increasing concentration of MGA, 17α-TB, or a combination of both. Survival among all treatments was not significantly different from controls. Amphibians exposed to MGA and 17α-TB in the environment may experience alterations in growth and development.
The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX, USA.
Bryson E
BE
Finch
Brett R
BR
Blackwell
Derek R
DR
Faust
Kimberly J
KJ
Wooten
Jonathan D
JD
Maul
Stephen B
SB
Cox
Philip N
PN
Smith
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004357:Drug Synergism; D054750:Ecotoxicology; D004625:Embryo, Nonmammalian / Q000187:drug effects; D004781:Environmental Exposure; D005938:Glucocorticoids / Q000633:toxicity; D007814:Larva / Q000187:drug effects; D008552:Melengestrol Acetate / Q000633:toxicity*; D009026:Mortality; D014204:Trenbolone Acetate / Q000633:toxicity*; D014982:Xenopus laevis / Q000196:embryology / Q000254:growth & development*
D005938:Glucocorticoids; D008552:Melengestrol Acetate; D014204:Trenbolone Acetate