Rodents testing

Fig. 4. FSH receptor-binding potencies of equine FSH ( ), eCG purified from pregnant mate s semm (O), and endometrial cups (A). Receptor-binding in ceU membrane fractions, B/Bq from (a) horse, (b) calf, and (c) rodent testes (40). Courtesy of Butterworth-Heinemaim.

Gy LD50, 30 days postexposure this species was the most radioresistant of 10 species of rodents tested 1... 

Testing in rodents. Especially important chemicals are further classified by rodent tests. So far only the mouse is used, but it would be good to broaden the basis for extrapolation to man by developing tests that use other small mammals. 

For especially difficult or important decisions, rodent tests are recommended (Figure 9-1). If the result is clearly positive, the substance is a mammalian mutagen,... 

The success of a mutagen assessment program depends strongly on the efficacy of the screening system, for most of the decisions regarding individual chemicals must be made on the basis of short-term screening tests. The criteria for choosing test systems are discussed in Chapter 6. On the basis of these criteria, the Committee has selected a set of tests, listed as "principal shortterm tests" in Table 9-1. Confirmatory rodent tests and supplementary tests are also listed. 

Six-Month Toxicology Study in Rodents2 ICH S4A Duration of Chronic Toxicity Testing in Animals (Rodent and Non-rodent Testing) 6-10 10-12 350,000-550,000... 

Additional tests may either be short or medium-term in vivo rodent test systems, usually using the mouse. These models of carcinogenesis may use transgenic or neonatal rodents. The guideline also includes models... 

Polychlorinated biphenyls (PCBs) have been used in the manufacturing of electrical transformers. They are highly persistent in the environment. Rodent tests have suggested that PCBs are carcinogenic and the U.S. government strongly regulates their production (Shelton, 1989). 

In the case of rodent tests reports continue to appear that stress the effect on survival of balanced diets" and of the time of day when the animal is irradiated. Even if one allows for the obvious differences between the bacteria and mouse test systems it is unfortunate that a better correlation between the two systems does not exist, even for a single class of drugs.A modification of the basic concepts of radiation dosimetry to Include a physical quantity other than absorbed dose was recommended to permit a better correlation with biological effects. ... 

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