Office of Program Operations

Michelle J. Hooth, Ph.D., D.A.B.T.
Michelle J. Hooth, Ph.D., D.A.B.T.
Deputy Director for Program Operations, Division of Translational Toxicology;
Director, Office of Program Operations
Tel 984-287-3140
Fax 919-541-4255
[email protected]
P.O. Box 12233
Mail Drop K2-07
Durham, NC 27709

Much of the work carried out by DTT is in support of the National Toxicology Program (NTP), an interagency partnership of the Food and Drug Administration, National Institute for Occupational Safety and Health, and NIEHS.

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Michelle Hooth, Ph.D., D.A.B.T. is a toxicologist and Chief of the Office of Program Operations in the Division of Translational Toxicology (DTT) at the National Institute of Environmental Health Sciences. As such, she is responsible for directing the work of chemists, toxicologists and information specialists involved in the study conduct portion of the testing program.

As a toxicologist, Hooth manages and participates in multidisciplinary teams of NTP and NIEHS scientists to develop research programs to address a broad array of toxicological study needs for chemicals selected for study by the National Toxicology Program. This includes the design, analysis, interpretation, and integration of general toxicology, carcinogenicity, and developmental and reproductive toxicity studies. She serves as a project leader for a diverse array of NTP test articles including metals, herbals, drinking water disinfection by-products and contaminants, and industrial compounds. She also aids in the coordination of the preparation and publication of the NTP technical reports including Toxicity, Technical, and Genetically Modified Model (GMM) reports providing scientific data and current knowledge of identified toxicants and carcinogens to regulatory agencies and the public.

Hooth received a B.S. (summa cum laude) in Biological Sciences from Michigan State University in 1990 and a Ph.D. in Toxicology from the University of North Carolina at Chapel Hill in 1996. She completed postdoctoral training in the Environmental Carcinogenesis Division of the National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency. She joined the NTP in 2000 as a staff scientist and became a Diplomate of the American Board of Toxicology in 2003. She is a member of the Society of Toxicology.

Selected Publications

  1. Roberts GK, Stout MD, Sayers B, Fallacara DM, Hejtmancik MR, Waidyanatha S, Hooth MJ. Clarification and lessons learned for reporting studies with hydrates. Citation: Roberts et al., 2016. Toxicology Reports 3: 531–538. Toxicology Reports 2018 5():207-208. [Abstract Roberts GK, Stout MD, Sayers B, Fallacara DM, Hejtmancik MR, Waidyanatha S, Hooth MJ. Clarification and lessons learned for reporting studies with hydrates. Citation: Roberts et al., 2016. Toxicology Reports 3: 531–538. Toxicology Reports 2018 5():207-208.]
  2. Harvey JB, Hong HH, Bhusari S, Ton TV, Wang Y, Foley JF, Peddada SD, Hooth M, DeVito M, Nyska A, Pandiri AR, Hoenerhoff MJ. F344/NTac Rats Chronically Exposed to Bromodichloroacetic Acid Develop Mammary Adenocarcinomas With Mixed Luminal/Basal Phenotype and Tgfβ Dysregulation. Veterinary pathology 2016 53(1):170-181. [Abstract Harvey JB, Hong HH, Bhusari S, Ton TV, Wang Y, Foley JF, Peddada SD, Hooth M, DeVito M, Nyska A, Pandiri AR, Hoenerhoff MJ. F344/NTac Rats Chronically Exposed to Bromodichloroacetic Acid Develop Mammary Adenocarcinomas With Mixed Luminal/Basal Phenotype and Tgfβ Dysregulation. Veterinary pathology 2016 53(1):170-181.]
  3. Hong HH, Hoenerhoff MJ, Ton TV, Herbert RA, Kissling GE, Hooth MJ, Behl M, Witt KL, Smith-Roe SL, Sills RC, Pandiri AR7. Kras, Egfr, and Tp53 Mutations in B6C3F1/N Mouse and F344/NTac Rat Alveolar/Bronchiolar Carcinomas Resulting from Chronic Inhalation Exposure to Cobalt Metal. Toxicologic pathology 2015 43(6):872-882. [Abstract Hong HH, Hoenerhoff MJ, Ton TV, Herbert RA, Kissling GE, Hooth MJ, Behl M, Witt KL, Smith-Roe SL, Sills RC, Pandiri AR7. Kras, Egfr, and Tp53 Mutations in B6C3F1/N Mouse and F344/NTac Rat Alveolar/Bronchiolar Carcinomas Resulting from Chronic Inhalation Exposure to Cobalt Metal. Toxicologic pathology 2015 43(6):872-882.]
  4. Behl M, Stout MD, Herbert RA, Dill JA, Baker GL, Hayden BK, Roycroft JH, Bucher JR, Hooth MJ. Comparative toxicity and carcinogenicity of soluble and insoluble cobalt compounds. Toxicology 2015 33():195-. [Abstract Behl M, Stout MD, Herbert RA, Dill JA, Baker GL, Hayden BK, Roycroft JH, Bucher JR, Hooth MJ. Comparative toxicity and carcinogenicity of soluble and insoluble cobalt compounds. Toxicology 2015 33():195-.]
  5. Harry GJ, Hooth MJ, Vallant M, Behl M, Travlos GS, Howard JL, Price CJ, McBride S, Mervis R, Mouton PR. (2014) Developmental Neurotoxicity of 3,3',4,4'-Tetrachloroazobenzene with Thyroxine Deficit: Sensitivity of Glia and Dentate Granule Neurons in the Absence of Behavioral Changes. Toxics 2(3):496-532. [Abstract Harry GJ, Hooth MJ, Vallant M, Behl M, Travlos GS, Howard JL, Price CJ, McBride S, Mervis R, Mouton PR. (2014) Developmental Neurotoxicity of 3,3',4,4'-Tetrachloroazobenzene with Thyroxine Deficit: Sensitivity of Glia and Dentate Granule Neurons in the Absence of Behavioral Changes. Toxics 2(3):496-532.]
  6. Waidyanatha S, Johnson JD, Hong SP, Robinson VG, Gibbs S, Graves SW, Hooth MJ, Smith CS. Toxicokinetics of α-thujone following intravenous and gavage administration of α-thujone or α- and β-thujone mixture in male and female F344/N rats and B6C3F1 mice. Toxicology and applied pharmacology 2013 271(2):216-228. [Abstract Waidyanatha S, Johnson JD, Hong SP, Robinson VG, Gibbs S, Graves SW, Hooth MJ, Smith CS. Toxicokinetics of α-thujone following intravenous and gavage administration of α-thujone or α- and β-thujone mixture in male and female F344/N rats and B6C3F1 mice. Toxicology and applied pharmacology 2013 271(2):216-228.]
  7. Mercado-Feliciano M, Herbert RA, Wyde ME, Gerken DK, Hejtmancik MR, Hooth MJ. Pyrogallol-associated dermal toxicity and carcinogenicity in F344/N rats and B6C3F1/N mice.  Cutaneous and ocular toxicology (2013) 32(3):234-240. [Abstract Mercado-Feliciano M, Herbert RA, Wyde ME, Gerken DK, Hejtmancik MR, Hooth MJ. Pyrogallol-associated dermal toxicity and carcinogenicity in F344/N rats and B6C3F1/N mice.  Cutaneous and ocular toxicology (2013) 32(3):234-240.]
  8. Witt, K. L., Stout, M. D., Herbert, R. A., Kissling G. E., Collins, B. J. and Hooth, M. J. (2013) Mechanistic insights from the NTP studies of chromium. Toxicologic Pathology 41(2):326-42.
  9. Hooth, M. J., Nyska, A., Fomby, L. M., Vasconcelos, D. Y., Vallant, M., DeVito, M. J. and Walker, N. J. (2012) Repeated dose toxicity and relative potency of 1,2,3,4,6,7-hexachloronaphthalene (PCN 66) and 1,2,3,5,6,7-hexachloronaphthalene (PCN 67) compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for induction of CYP1A1, CYP1A2 and thymic atrophy in female Harlan Sprague-Dawley rats. Toxicology 301:85-93.
  10. Ramot, Y., Vered, M., Malareky, D., Hooth, M., Painter, J., Dayan D., Clayton, N., Marsh, T., and Nyska, A. (2012) Immunohistochemical Features of 3, 3, 4, 4-Tetrachloroazobenzene-Induced Rat Gingival Lesions. Toxicologic Pathology 40(4):577-92.
  11. Cheng, Y., Wright, S. H., Kuester, R. K., Hooth, M. J., and Sipes, I. G. (2011) Characterization of the inhibitory effects of N-butylpyridinium chloride and structurally related ionic liquids on kidney organic cation transporters. Drug Metabolism and Disposition 39(9): 1755-61.
  12. Collins, B. J., Stout, M. D., Levine, K. E., Kissling, G. E., Melnick R. L., Fennell, T. R., Walden, R., Pritchard, J. B., Fernando, R. A., Burka, L. T. and Hooth, M. J. (2010). Exposure to hexavalent chromium resulted in significantly higher tissue chromium burden compared with trivalent chromium following similar oral doses to male F344/N rats and female B6C3F1 mice. Toxicological Sciences 118(2):368-379.
  13. Singh, B. P., Nyska, A., Kissling, G. E., Lieuallen, W., Johansson, S. L., Malarkey, D. E., and Hooth, M. J. (2010) Urethral carcinoma and hyperplasia in male and female B6C3F1 mice treated with 3,3’,4,4’- tetrachloroazobenzene (TCAB). Toxicologic Pathology 38(3):372-381.
  14. Ramot, Y., Nyska, A., Lieuallen, W., Maly A., Zlotogorski, A., Flake, G., Kissling G. E., Brix, A., Malarkey, D. E., and Hooth, M. J. (2009) Inflammatory and chloracne-like skin lesions in B6C3F1 mice exposed to 3,3’,4,4’-tetrachloroazobenzene for 2 years. Toxicology 265(1-2): 1-9.  
  15. Knudsen, G.A., Cheng, Y., Kuester, R. K., Hooth, M. J. and Sipes, I. G. (2009). Effects of dose and route on the disposition and kinetics of 1-butyl-1-methylpyrrolidinium chloride in male F344 rats. Drug Metabolism and Disposition 37(11): 2171-2177.
  16. Stout, M. D., Herbert, R. A., Kissling, G. E., Collins, B. J., Travlos, G. S., Witt, K. L., Melnick R. L., Abdo, K. M., Malarkey, D. E., and Hooth, M. J. (2009) Hexavalent chromium is carcinogenic to F344/N rats and B6C3F1 mice following chronic oral exposure. Environmental Health Perspectives 117(5): 716-722.
  17. Cheng Y., Wright, S. H., Hooth, M. J., and Sipes, I. G. (2009) Characterization of the disposition and toxicokinetics of N-butylpyridinium chloride in male F344 rats and female B6C3F1 mice and its transport by organic cation transporter 2. Drug Metabolism and Disposition, 37(4): 909-916.
  18. Stout, M. D., Nyska A., Collins, B. J., Witt, K. L., Kissling, G. E., Malarkey, D. E., and Hooth, M. J. (2009) Chronic toxicity and carcinogenicity studies of chromium picolinate monohydrate administered in feed to F344/N rats and B6C3F1 mice for 2 years. Food and Chemical Toxicology, 47(4): 729-733.
  19. Hooth, M. J., Herbert, R. A., Haseman, J. K., Orzech, D. P., Johnson, J. D. and Bucher, J. R. (2004) Toxicology and carcinogenesis studies of dipropylene glycol in rats and mice. Toxicology, 204(2-3): 123-140
  20. Hooth, M. J., Sills, R. C., Burka, L. T., Haseman, J. K., Witt, K. L., Orzech, D. P., Fuciarelli, A. F., Graves, S. W., Johnson, J. D. and Bucher, J. R. (2004) Toxicology and carcinogenesis studies of microencapsulated trans-cinnamaldehyde in rats and mice. Food and Chemical Toxicology, 42(11): 1757-1768.
  21. McDorman, K. S., Chandra, S., Hooth, M. J., Hester, S. D., Schoonhoven, R., and Wolf, D. C. (2003) Induction of transitional cell hyperplasia in the urinary bladder and aberrant crypt foci in the colon of rats treated with individual and a mixture of drinking water disinfection by-products. Toxicologic Pathology, 31(2): 235-242.
  22. McDorman, K. S., Hooth, M. J., Starr, T. B., and Wolf, D.C. (2003) Analysis of preneoplastic and neoplastic renal lesions in Tsc2 mutant Long-Evans (Eker) rats following exposure to a mixture of drinking water disinfection by-products. Toxicology, 187(1): 1-12.
  23. Hooth, M. J., McDorman, K. S., Hester, S. D., George, M. H., Brooks, L. R., Swank, A. E., and Wolf, D. C. (2002) The carcinogenic response of Tsc2 mutant Long-Evans (Eker) rats to a mixture of drinking water disinfection by-products was less than additive. Toxicological Sciences, 69(2): 322-331.
  24. Hooth, M. J., DeAngelo, A. B., George, M. H., Gaillard, E. T., Travlos, G. S., Boorman, G. A., and Wolf, D. C. (2001) Subchronic sodium chlorate exposure in drinking water results in a concentration-dependent increase in rat thyroid follicular cell hyperplasia. Toxicologic Pathology 29(2): 250-259.