M520

Inbr. F148.

Colour: Albino.

Genet. a, c, h.

Origin: Curtiss 1920, Columbia University Institute for Cancer Research, to Heston in 1949 at F49. To NIH in 1951 at F51 (Hansen et al 1982). A congenic strain lacking vasopressin due to the presence of the diabetes insipidus gene, di (from the Brattleboro rat) has been described (Colombo et al, 1992).

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Characteristics

Low systolic blood pressure (16/17) (Hansen et al 1973). Low hepatic metabolism of anilene (9/10 in males, 7/10 in females), but high metabolism of ethylmorphine (1/10) (Page and Vesell 1969). Good breeding performance (2/12) and intermediate litter size (6/12) (Hansen et al 1973). Susceptible to Cysticercus. NIH subline has a 21-25% incidence of adrenal medulla tumours. Susceptible to induction of tumours by 2-acetylaminofluorine (Symeonidis 1954). Low frequency of pancreatic exocrine tumours. By 12-15 months of age develop small local areas of nephritis that progress by 22-24 months to moderate to severe nephritis in 75% of animals (Snell 1967). About 33% of females over 18 months develop tumours of the uterus of endometrial origin. Adrenocortical adenomas (about 20% in males and 40% in females over 18 months of age), and phaeochromocytomas or preneoplastic nodules in adrenal medulla (about 67% of males over 21 months of age) (Snell 1965). Intermediate survival to 2 years of age at 59% in males and 62% in females. There was a relatively high incidence of mild chronic renal disease and a high incidence of hydronephrosis which may make the strain unsuitable for long-term toxicity studies (though diet may have an important influence) (Solleveld and Boorman 1986). Low blood pressure (21/23), reaching 121_1.2 (SEM) mmHg at 10 weeks of age (Tanase et al 1982). Resistant to development of methlycholanthrene -induced thyroiditis (Glover et al 1969). Low antibody response to streptococcal group A carbohydrate, which is not MHC linked (Stankus and Leslie 1976). Low 10-week body weight in males (5/23) (Tanase et al 1982). High relative heart weight in 10-week old males (21/23) (Tanase et al 1982).

Lacks the phenobarbital-inducible cytochrome P450 2B2 (Cyp2B2) in hepatic microsomes due to a mutation in a single autosomal gene, with codominant inheritance with respect to protein and mRNA phenotypes (see also MW) (Omiecinski et al, 1992).

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Colombo G., Hansen C., Hoffman P. L., and Grant K. A. (1992) Decreased performance in a delayed alternation task by rats genetically deficient in vasopressin. Physiol. Behav. 52, 827-830.

Glover E. L., Reuber M. D., and Godfrey F. (1969) Methylcholanthrene-induced thyroiditis. Susceptibility of Buffalo strain rats. Arch. Environ. Health 18, 901-903.

Hansen C. T., Judge F. J., and Whitney R. A. (1973) Catalogue of NIH Rodents. DREW Publ. No. 74-606. Department of Health, Education, and Welfare, Washington, D.C.: U.S.

Hansen C. T., Potkay S., Watson W. T., and Whitney R. A. Jr. (1982) NIH Rodents: (1980). Catalogue. NIH Publ. No. 83-606. Department of Health and Human Services, Washington, D.C.: U.S.

Omiecinski C. J., Ramsden R., Rampersaud A., and Walz F. G. (1992) Null phenotype for cytochrome-P450-2b2 in the rat results from a deletion of its structural gene. Molec. Pharmacol. 42, 249-256.

Page J. G. and Vesell E. S. (1969) Hepatic drug metabolism in ten strains of Norway rat before and after pretreatment with phenobarbital. Proc. Soc. Exp. Biol. Med. 131, 256-261.

Snell K. C. (1965) Spontaneous lesions of the rat, in The Pathology of Laboratory Animals (Ribelin W. E. and McCoy J. R., eds), pp. 241-302. Charles C. Thomas, Springfield, Illinois.

Snell K. C. (1967) Renal disease of the rat, in Pathology of Laboratory Rats and Mice (Cotchin E. and Roe F. J., eds), pp. 105-147. Blackwell Scientific, Oxford.

Stankus R. P. and Leslie G. A. (1976) Rat interstrain antibody response and crossidiotypic specificity. Immunogenet. 3, 65-73.

Symeonidis A. (1954) Tumors induced by 2-acetylaminofluorene in virgin and breeding females of five strains of rats and in their offspring. J. Natl. Cancer Inst. 15, 539-549.

Tanase H., Yamori Y., Hansen C. T., and Lovenberg W. (1982) Heart size in inbred strains of rats. Part 1. Genetic determination of the development of cardiovascular enlargement in rats. Hypertension 4, 864-872.

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INBRED STRAINS OF RATS
Updated 9 Apr. 1998
Michael FW Festing
MRC Toxicology Unit, Hodgkin Building,
University of Leicester, UK