OM

Genotype:

Pigmentation genes: aa BB cc hh PP RR

Mhc: RT1^uv3(RT1.A^uB/D^uC^uv3)

Erythrocyte antigens:RT2 ^b RT8 ^b

Lymphocyte antigens:RT6 ^b RT7 ^b

Inbr. Gen.: At Ztm (1998), F21.

Origin: Heston, 1946, from outbred Osborne-Mendel stock. To N in 1951 at F10 (3), to Han, to Ztm in 1994.

Reproduction: Good reproductive performance. Average litter size 7,16 and 0,81 young weaned/female/week.

Tumours (Spontaneous): Incidence of spontaneous thyroid carcinoma 33% in animals over 24 months of age (4). In animals over 18 months of age incidence of adenomas or carcinomas of the adrenal cortex 73% of males and 95% of females, pituitary tumours 25%, granulosa cell tumours of the ovary 33% in females (8).

Tumours (Induced): 2-Acetylaminofluorene induces mammary tumours in females (10). Other Characteristics: High incidence of retinal degeneration in animals over 10 months of age (11, 12). Relatively resistant to development of nephritis (9). Resistant to 3-methylcholanthrene-induced thyroiditis (2). Very susceptible to chronic respiratory disease. Becomes obese on a high fat diet (5). Genetic marker profile described by Bender et al. (1994) (1). Used in studies on the effects of fluoride rinses on fluoride uptake in tooth enamel and on dental plaque (6, 7).

References:

1. Bender, K., P. Balogh, M.F. Bertrand, M. den Bieman, O. van Deimling, S. Eghtessadi, G.A. Gutman, H. J. Hedrich, S.V. Kluge, K. Matsumoto, D.H. Moralejo, M. Nagel, A. Portal, C.-M. Prokop, R.T. Seibert and L.F.M. van Zutphen. 1994. Genetic characterization of inbred strains of the rat (Rattus norvegicus). I. Exp. Anim. Sci. 36: 151-166.

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

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

4. Lindsay, S., C. W. Nichols, Jr., and I. L. Chaikoff. 1968. Naturally occurring thyroid carcinoma in the rat. Similarities to human medullary carcinoma. Arch. Pathol. 86: 353 364.

5. Schemmel, R., O. Mickelsen, and J. L. Gill. 1970. Dietary obesity in rats: Body weight and body fat accretion in seven strains of rats. J. Nutr. 100: 1041 1048.

6. Shern, R. J. and K. M. Couet. 1979. Effects of stannous fluoride and tiodonium chloride on dental plaque in rats.J. Dent. Res. 58: 1830 1835.

7. Shern, R. J., K. M. Couet, L. C. Chow, and W. E. Brown. 1979. Effects of sequential calcium phosphate Fluoride rinses on fluoride uptake in rats. J. Dent. Res. 58(B): 1023 (abstr.).

8. Snell, K. C. 1965. Spontaneous lesions of the rat. In W. E. Ribelin and J. R. McCoy, eds., The Pathology of Laboratory Animals, 241 302, Charles C. Thomas, Springfield, Ill, USA.

9. Snell, K. C. 1967. Renal disease of the rat. In E. Cotchin and F. J. Roe, eds. , Pathology of Laboratory Rats and Mice, 105 147, Blackwell Scientific Publications, Oxford.

10. 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.

11. von Sallmann, L. and P. Grimes. 1972. Spontaneous retinal degeneration in mature Osborne-Mendel rats. Arch. Ophthalmol. 88: 404 411.

12. von Sallmann, L. and P. Grimes. 1974. Retinal degeneration in mature rats. Comparison of the disease in an Osborne-Mendel and a spontaneously hypertensive Wistar strain. Invest. Ophthalmol. 13: 1010 1015.