NEW CONGENIC RAT STRAINS FOR THE SEPARATE STUDY OF MHC AND NON-MHC GENETIC-EFFECTS IN THE DEVELOPMENT OF DIABETES IN BB RATS

Diabetes in BB rats is genetically determined by at least two genes, the one gene mapping to the MHC, the other residing in the genetic background. In order to be able to study the role of MHC and non-MHC genes in diabetogenesis we have established rat strains which combine the diabetes-resistent LEW genetic background with the RT1u haplotype of diabetic BB rats (LEW.1BB) or carry the diabetes-resistent RT1 haplotype of LEW.1A rats on the diabetic BB genetic background (BB.1A). BB rats of two different sublines (BB/OK and BB/PhiK) were used for this purpose. In these rat strains diabetes relevant traits were studied longitudinally, the RT1 haplotypes were analyzed at DNA level and 18 non-MHC linked immunogenetic and enzyme loci were monitored. The results demonstrate the successful transfer of genes with potential relevance for diabetes development in BB rats.