CHARACTERIZATION OF THE HEREDITY OF KININOGEN DEFICIENCY IN BROWN NORWAY KATHOLIEK STRAIN RATS

Brown Norway rat strain has been studied for mode of inheritance of its congenital deficiency in plasma high molecular weight (HMW)-kininogen and low molecular weight (LMW)-kininogen, and low plasma level of prekallikrein. We examined the genetics of the deficiency by performing a mixed breeding experiment between B/N-Katholiek (B/N-Ka, deficient) and B/N-Kitasato (B/N-Ki, normal) strains. Incidence of the deficiency was judged by the plasma level of HMW-kininogen. Plasma level of HMW-kininogen was around 50% of the normal level in all F1 generations of the hybrid between male B/N-Ka and female B/N-Ki (Exp.1), and between female B/N-Ka and male B/N-Ki (Exp.2). Incidence of deficiency (plasma HMW-kininogen level < 5%) in Exp.1 was 23.8% in male F2 and 20.0 % in female F2 generations. By Exp.2 also the incidence was 25.0 % in male and 30.0 % in female F2 generations. There was no significant difference of the incidence between the two experiments or sexes. These results indicate the inheritance of the kininogen-deficiency to be Mendelian autosomal recessive, the same as for the reported cases of human kininogen deficiency. Gel filtration study suggests that prekallikrein in the B/N-Ka plasma may be free form, while that in the B/N-Ki plasma may form complex with HMW-kininogen.