U.S. National Toxicology Program

Huff JE, McConnell EE, Haseman JK, et al. 1988. Carcinogenesis studies results of 398 experiments on 104 chemicals from the U.S. National Toxicology Program. In Maltoni C., Selikoff I.J., ed. Annals of the New York Academy of Sciences. Living in a Chemical World Occupational and Environmental Significance of Industrial Carcinogens. Vol. 534, New York, NY New York Academy of Sciences, 1 -30. 

Mononuclear Cell Leukemia (MNCL) is unique to the rat, and is only common in the F-344 (common name Fischer rat) inbred rat strain, which is the strain used by the U.S. National Toxicology Program (NTP). Elevated incidences of MNCL have been observed in a number of chronic bioassays in the F-344 rat. The frequency differs between males and females, with an incidence in males around 50%, and an incidence in females around 30%, with a large variation from study to study. It has been shown for some genotoxic carcinogens that exposure does not lead to an increase in MNCL in the F-344 rat, while a number of substances, which are believed to be noncarcinogens,... 

Lewis (1993, as cited in Dourson et al. 1996) performed an analysis of subchronic-to-chronic NOAEL ratios based on peer-reviewed hterature or information from NTP (U.S. National Toxicology Program). Criteria for inclusion in their analysis were rigorous and of 54 chemicals considered,... 

Tennant, R.W. and Ashby, J., Classification according to chemical structure, mutagenicity to Salmonella and level of carcinogenicity of a further 39 chemicals tested for carcinogenicity by the U.S. National Toxicology Program, Mutat. Res., 257, 209-227, 1991. 

Benigni, R., Andreoli, C., and Zito, R., Prediction of the carcinogenicity of further 30 chemicals biossayed by the U.S. National Toxicology Program, Environ. Health Perspect., 104 (Suppl. 5), 1041-1044, 1996. 

NTP (U.S. National Toxicology Program) Division of Toxicology Research and Testing, published reports. 

NTP and CPDB refer to the U.S, National Toxicology Program carcinogenicity assays (45) and to the Carcinogenic Potency Data Bases (46), respectively. 

In a study carried out by the U.S. National Toxicology Program, laboratory animals were watered with water containing a mixture of 25 common groundwater contaminants at environmentally relevant levels. The chemicals, which included many lipophiles and hydrophiles, included aromatic hydrocarbons, chlorinated... 

Conversion of ingested substances to less active forms by GI enz)unes or the acidic environment of the stomach is a factor for some environmental contaminants. Hexavalent chromium provides a good example, because it can be rapidly reduced to the relatively nontoxic bivalent form in the stomach. The recently completed positive cancer bioassay on hexavalent chromium conducted by the U.S. National Toxicology Program (NTP) appears to indicate, however, that this conversion is not complete at the concentrations administered (NTP 2007). 

The findings of biochemical effects in preclinical toxicology studies are relatively common Heywood (1981, 1983) found more than 30% of a mixture of tested compounds affected blood chemistry measurements in rats, dogs, and monkeys there were species differences, and these findings were less common in monkeys. In 61 subchronic rat studies conducted by the U.S. National Toxicology Program, liver and kidney lesions were reported in 31 and 41% of the studies, respectively (Travlos et al. 

Studies on experimental animals have indicated its tumorigenic potency. Repeated inhalation of dimethyl snlfate vapors cansed tumors of nasal cavity and thorax in rats. Repeated subcutaneous injections of the liq-nid produced local sarcomas. In hnmans, however, its carcinogenicity has not been established. The U.S. National Toxicology Program has classified this componnd as Reasonably anticipated to be carcinogenic to human (NTP 1998). 

A REVIEW OF FINDINGS FROM THE U.S. NATIONAL TOXICOLOGY PROGRAM S EXPERT PANEL REPORTS... 

Due to the widespread use of phthalates, it is important to consider human exposure and public health implications of such exposure. This review will focus on the following phthalates which were the subject of recent evaluations of risks to human reproduction by the U.S. National Toxicology Program, NTP, National Institutes of Environmental Health Sciences, NIEHS butyl benzyl phthalate, BBP di-isodecyl phthalate, DIDP di-isononyl phthalate, DINP DBP di-n-hexyl phthalate, DnHP di-n-octyl phthalate, DnOP a DEHP. 

U.S. National Toxicology Program, Center for the Evalnation of Risks to Hnman Reprodnction. 2007. NTP-CERHR reports and monographs. National Institnte of Health. Downloaded from http //ntp.niehs.nih.gov/ntp/ohat/hisphenol/hisphenol.pdf. Accessed October 7, 2014. 

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