Exposure to low concentrations of di-n-butyl phthalate during embryogenesis reduces survivability and impairs development of Xenopus laevis frogs.
Di-n-butyl phthalate (DBP) appears to be a ubiquitous environmental contaminant, as indicated by its presence in air, water, and soil worldwide (Giam et al., 1980; ATSDR, 2001; Peterson & Freeman, 1982) and the presence of its major metabolite, monobutyl phthalate (MBP), in random human urine samples (Blount et al., 2000). Studies indicate that exposure to a variety of endocrine-disrupting chemicals, such as DBP, may be partially responsible for reported global amphibian declines; if so, amphibians may serve as ecological harbingers for the future of human health. Therefore, this study was undertaken to investigate the effects of environmentally relevant concentrations of DBP on development in Xenopus laevis African clawed frogs. Developmental effects of DBP on Xenopus embryos were determined using the 96-h frog embryo teratogenesis assay-Xenopus (FETAX). Embryos (n = 300/group) were exposed from gastrulation (stage 8-11) through primary organogenesis (stage 46) to 0.1, 0.5, 1, 5, 10, or 15 ppm DBP dissolved in 0.01% dimethyl sulfoxide (DMSO), vehicle alone (0.01% DMSO; solvent control), or FETAX culture medium only (control; n = 600). At 96 h, mortalities for control, solvent control, and 0.1, 0.5, 1, 5, 10, and 15 ppm DBP were 5, 4, 6, 5, 5, 9, 18, and 52%, respectively; the incidence of developmental malformations in the surviving tadpoles was 7, 9, 15, 37, 51, 53, 90, and 100%. The average length of embryos was significantly lower in all DBP treatment groups. Thus, DBP significantly affected development of Xenopus embryos at low, environmentally relevant concentrations.
Lee
Shannon K
SK
Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, Colorado 80253-1683, USA.
Owens
Gwen A
GA
Veeramachaneni
D N Rao
DN
D000014:Abnormalities, Drug-Induced; D000818:Animals; D002470:Cell Survival / Q000187:drug effects*; D003993:Dibutyl Phthalate / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D038081:Organogenesis / Q000187:drug effects*; D013723:Teratogens; D014982:Xenopus laevis
D013723:Teratogens; D003993:Dibutyl Phthalate