Spontaneous and methylcholanthrene-enhanced thyroiditis in BUF rats. I. The incidence and severity of the disease, and the genetics of susceptibility.

Virgin female Buffalo strain (BUF) rats that were treated with methylcholanthrene (MC) had a higher incidence of lymphocytic thyroiditis than untreated BUF rats. The degree of infiltration was also greater in MC-treated rats. The incidence of thyroiditis in retired breeder female BUF rats approached that found in MC-treated rats. The susceptibility to the effect of MC was not expressed in most F-1 hybrids of BUF and Lewis (LEW), a strain of rat that does not develop thyroiditis after treatment with MC.