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Katie B. Paul

Education

Doctorate of Philosophy
Curriculum in Toxicology
Research Advisor: Drs. Kevin Crofton and Mike DeVito
Academic Advisor: Dr. Kevin Crofton
Date of Matriculation: August 2006

Bachelor of Science in Biochemistry
Minor in Chemistry
Minor in Environmental Policy & Planning
Virginia Tech, Blacksburg, VA, May 2006

Publications and Recent Abstracts

Paul KB, Hedge JM, Crofton KM, DeVito MJ. “Triclosan Alters Thyroid Hormone Homeostasis via Up-regulation of Hepatic Catabolism.” To be presented at the 2008 Annual Meeting of the Society of Toxicology (March 2008).

Paul KB, Hedge JM, DeVito MJ, Crofton KM. “Triclosan and endocrine disruption: Evidence for alterations in thyroid hormone homeostasis.” Presented at the Society of Environmental Toxicology and Chemistry 2007 Annual Meeting in Milwaukee, WI (November 2007).

Crofton KM, Paul KB, DeVito MJ, Hedge JM. (2007) “Triclosan and endocrine disruption: Evidence for alterations in thyroid hormone homeostasis.” Environmental Toxicology and Pharmacology. 24, 194-197.

Awards

3rd Place, Poster Presentation, Curriculum in Toxicology Annual Retreat (January 2008)

Graduate Student Travel Award, Society for Environmental Toxicology and Chemistry’s 2007 Annual Meeting in Milwaukee, WI (November 2007)

Undergraduate Student Travel Award, American Society for Biochemistry and Molecular Biology, 2006 Experimental Biology Meeting in San Francisco, CA (May 2006)

Undergraduate Research Award, Sigma Xi National Research Society (May 2006)

Biochemistry Department Student Research Award, Virginia Tech Dept. of Biochemistry (May 2006)

Dissertation

Proposal in progress; related to thyroid disruption, risk assessment, neurodevelopment, interspecies differences
Advisor: Dr. Kevin Crofton

Current Research (Fall 2007)

Triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) is a chlorinated phenolic antibacterial compound used in household and hygiene products. The structural similarity of triclosan to thyroid hormones, in vitro studies demonstrating activation of the human pregnane X receptor (PXR) and inhibition of sulfotransferases, and dose-dependent decreases in vivo of total thyroxine (T4) suggest adverse effects on thyroid hormone homeostasis. Current research tested the hypothesis that triclosan decreases circulating concentrations of T4 via activation of PXR, constitutive androstane receptors (CAR), and subsequent up-regulation of hepatic catabolism of hormones. Female Long-Evans rats (24 days old) were exposed po to triclosan (0-1000 mg/kg/day) for four days. Whole blood and liver were collected 24 hr after the last dose. Hepatic microsomal assays measured ethoxyresorufin-O-deethylase (EROD), pentoxyresorufin-O-deethylase (PROD), and uridine diphosphate glucuronyltransferase (UGT) enzyme activities. mRNA expression of UGT1A1, and sulfotransferase 1C1 were measured by quantitative RT-PCR. Triclosan caused a dose-dependent increase in PROD activity (up to 5-fold at 300 mg/kg/day). There was no biologically relevant change in EROD activity. T4-glucuronidation increased ~2-fold at 100 mg/kg/day. UGT1A1 mRNA expression increased in a dose-dependent manner (up to 2.2-fold at 300 mg/kg/day). These data suggest that triclosan-induced hypothyroxinemia is, at least partially, due to upregulation of hepatic catabolism. This abstract does not necessarily reflect the policy of the US EPA. K. Paul supported by NIEHS T32-ES07126.

Professional Membership

Society of Toxicology (2008–present)

Society of Environmental Toxicology and Chemistry (2007–present)

Sigma Xi, The National Research Honor Society (2006–present)

American Society for Biochemistry and Molecular Biology (2005–present)

Community Outreach

Mentor, Women and Math Mentoring Program, Durham County Schools (2007–2008)

Genetics Instructor, Johns Hopkins University Center for Talented Youth (2007)

Chairman, Virginia Tech University Honors $10K Project Proposal (2006)

Coordinator, Save Our Streams Program, American Water Resources Association VT Chapter (2004–2006)

Personal Interests

Environmental policy and conservation, reading, painting, drawing, running, swimming, vegetarian cooking