Grantee Research Project Results
2004 Progress Report: Impact of Phthalates on the Male: Frog and Rabbit Models
EPA Grant Number: R829429Title: Impact of Phthalates on the Male: Frog and Rabbit Models
Investigators: Veeramachaneni, D. N. Rao
Institution: Colorado State University
EPA Project Officer: Aja, Hayley
Project Period: March 1, 2002 through February 28, 2005 (Extended to February 28, 2007)
Project Period Covered by this Report: March 1, 2004 through February 28, 2005
Project Amount: $852,709
RFA: Children's Vulnerability to Toxic Substances in the Environment (2001) RFA Text | Recipients Lists
Research Category: Children's Health , Human Health , Environmental Justice
Objective:
The objective of this research project is to test the hypothesis that exposure to dibutyl phthalate (DBP) during differentiation of the reproductive system, even at relatively low concentrations, alters reproductive function as adults. This hypothesis is being tested in two animal models, an amphibian, Xenopus laevis, and a nonrodent mammal, the rabbit. The former facilitates transdermal exposure and evaluation of an easy-to-monitor, unique thyroid hormone-dependent event, the metamorphosis, whereas the latter facilitates longitudinal evaluations of hormones, semen parameters, and sexual capacity. Furthermore, rabbits, unlike rodents, have a relatively long infantile period of reproductive development more closely approximating the situation in humans. Dermal route of exposure is particularly pertinent to children’s vulnerability to toxic substances in the environment, as children have a greater ratio of surface area to body weight than adults.
Progress Summary:
All phases of animal experimentation of the rabbit component were completed. Sperm morphology and histopathological evaluations of testicular tissue are in progress. Two of three experiments utilizing the X. laevis model have been completed and results published. Analyses of the third experiment (exposure from organogenesis through metamorphosis) are in progress.
The research indicates that exposure of X. laevis to DBP at concentrations as low as 0.1 ppm inhibits growth of tadpoles and impairs spermatogenesis. In addition, the developmental exposure of male rabbits to DBP results in germ cell atypia.
Future Activities:
Sperm morphology and histopathological evaluations of all rabbit research and histopathological evaluations of the third experiment in frog research will be performed during the coming year. No hurdles in the conduct of the remaining procedures are anticipated.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
Other project views: | All 16 publications | 4 publications in selected types | All 4 journal articles |
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Lee SK, Owens GA, Veeramachaneni DNR. Exposure to low concentrations of di-n-butyl phthalate during embryogenesis reduces survivability and impairs development of Xenopus laevis frogs. Journal of Toxicology and Environmental Health, Part A 2005;68(10):763-772. |
R829429 (2004) R829429 (2005) R829429 (Final) |
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Lee SK, Veeramachaneni DNR. Subchronic exposure to low concentrations of di-n-butyl phthalate disrupts spermatogenesis in Xenopus laevis frogs. Toxicological Sciences 2005;84(2):394-407. |
R829429 (2004) R829429 (2005) R829429 (Final) |
Exit Exit |
Supplemental Keywords:
abnormal male sexual differentiation, testicular dysgenesis, transdermal exposure, metamorphosis, dibutyl phthalate, sperm morphology, histopathological evaluations, Xenopus laevis model,, RFA, Health, Scientific Discipline, Toxicology, Health Risk Assessment, Chemistry, Risk Assessments, Disease & Cumulative Effects, Children's Health, Ecological Risk Assessment, Biology, risk assessment, frog deformities, dermal contact, animal model, phtalates, children, fertility, Human Health Risk Assessment, reproductive development, human exposure, children's environmental health, exposure pathways, animal studies, reproductive health, reproductive function, diopathic infertility, exposure assessment, human health riskProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.