Carcinogenicity studies Sprague-Dawley rats

The duration of carcinogenicity studies for both rats and mice is two years in most pharmaceutical laboratories (PMA, 1988). Occasionally, rat studies are extended to 30 months, while some companies terminate mouse studies at 18 months. The difference in duration between mouse and rat studies is based on the behef that rats have a longer natural hfe span than mice. Recent data indicate, however, that this is not the case. The most commonly used strains, the Sprague-Dawley rat and the CD-1 mouse, have approximately equal survival at two years, based on industry data (PMA, 1988). The same is true for the most popular inbred strains, the Fischer 344 rat and the B6C3F1 mouse (PMA, 1988). Data from NCI studies confirm that the two-year survival of the B6C3F1 mouse is at least equal to, if not greater than, that of the Fischer 344 rat (Cameron et al., 1985). 

The carcinogenicity of decaBDE was also evaluated in Sprague-Dawley rats (25/sex/dose) that were exposed to dietary doses of 0, 0.01, 0.1, or 1.0 mg/kg/day for approximately 2 years (702 days for males, 735 days for females) (Kociba et al. 1975 Norris et al. 1975b). The commercial mixture was comprised of 77.4% decaBDE, 21.8% nonaBDE, and 0.8% octaBDE and therefore differs from typical decaBDE formulations containing 97% decaBDE. Comprehensive histological examinations showed no exposure-related neoplastic effects. Tlie ability of this study to detect carcinogenic changes is limited by the very low dose levels in comparison to those tested in the NTP (1986) bioassay. 

Trichloroethane was tested for carcinogenicity in a two-year study in male and female B6C3F] mice and Osborne-Mendel rats by oral administration and in Sprague-Dawley rats by subcutaneous injection. In the study by oral administration, 1,1,2-trichloroethane produced hepatocellular neoplasms and adrenal phaeochromocytomas in mice of each sex but did not significantly increase the proportion of rats with neoplasms at any site relative to untreated controls. In the study in rats by subcutaneous injection,... 

Krowke et al. (1989) were analyzed. The former study provided dose-response characterization of concentrations of 2,3,7,8-TCDD in liver and of liver CYP1A1 activity and time-course characterization of 2,3,7,8-TCDD concentration in tissues and enzyme activities in female Wistar rats. Krowke et al. (1989) examined liver and fat concentrations in male Wistar rats dosed weekly for up to 6 months. In addition, Andersen et al. (1993) examined the potential correlation between several measures of dose estimated by the model and the promotional efficacy and carcinogenicity of 2,3,7,8-TCDD in Sprague-Dawley rats. Cancer data from Kociba et al. (1978a) and Pitot et al. (1980) were analyzed. 

Carcinogenicity Study in Sprague-Dawley Rats ICH S1A The Need for Long-term Rodent Carcinogenicity Studies of Pharmaceuticals and ICH SIB Testing for Carcinogenicity of Pharmaceuticals (2yr) 8-10 26-30 1-1.5 M... 

The study by Albert et al. (1982) reported the carcinogenic responses to the combined and separate exposures to formaldehyde and hydrochloric acid in male inbred Sprague-Dawley rats. Rats were exposed for 588 days to formaldehyde alone (14.2 ppm) formaldehyde (14.1 ppm) and hydrogen... 

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