National Toxicology Program

DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service

National Toxicology Program (NTP); Availability of Technical Report of Comparative Initiation/Promotion Skin Paint Studies of B6C3F1 Mice, Swiss (CD-1®) Mice, and SENCAR Mice

The HHS' National Toxicology Program announces the availability of the NTP Technical Report on the Comparative Initiation/Promotion Skin Paint Studies of B6C3F1 Mice, Swiss (CD-1®) Mice, and SENCAR Mice.

All three strains of mice demonstrated sensitivity by developing skin tumors after topical application of the chemicals under study (7,12-dimethylbenz(a)anthracene (DMBA), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 12-O-tetradecanoylphorbol-13-acetate (TPA), and benzoyl peroxide (BPO). The most sensitive of the three strains appeared to be SENCAR mice, in the sense that lower doses of the test chemical were generally required to produce effects equivalent to those in the other two strains. Skin tumors also tended to develop earlier and with greater multiplicity in SENCAR mice than in the other two strains. By these criteria, the overall sensitivity of Swiss (CD­1®) mice was intermediate, and B6C3F1 mice showed the least overall sensitivity to dermal carcinogenicity.

The 1­year complete carcinogen studies used repeated applications of low concentrations of the carcinogens DMBA and MNNG. There was a high incidence of skin tumors in all three strains with both carcinogens. More B6C3F1 and SENCAR mice developed skin tumors and averaged more tumors per mouse than did Swiss (CD­1®) mice. Skin tumors developed earlier in SENCAR mice than in B6C3F1 and Swiss (CD­1®) mice. Although B6C3F1 mice exhibited the lowest overall sensitivity to the initiation/promotion protocol when compared to Swiss (CD­1®) and SENCAR mice, the response of B6C3F1 mice was similar to Swiss (CD­1®) and SENCAR mice for complete carcinogen studies.

Questions or comments about the Technical Report should be directed to Central Data Management at NIEHS, MD E1-02, P.O. Box 12233, Research Triangle Park, NC 27709 or telephone (919) 541-3419.

Copies of the Comparative Initiation/Promotion Skin Paint Studies of B6C3F1 Mice, Swiss (CD-1®) Mice, and SENCAR Mice(TR-441) are available without charge from Central Data Management, NIEHS, MD E1-02, P.O. Box 12233, Research Triangle Park, NC 27709; telephone (919) 541-3419 or send e-mail to CDM@niehs.nih.gov.

Dated: August 21, 1996

 
________________________________
Kenneth Olden, Ph.D.
Director
National Toxicology Program

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