Abstract
The natural history of hereditary hepatitis in long-survived LEC rats was reported. Among 56 (female: male, 28:28) LEC rats of F30, 16 (8:8) (29%) died of fulminant hepatitis approximately four months after birth. The remaining 40 (20:20) rats that survived more than one year developed chronic hepatitis and subsequent hepatic lesions including hepatocellular carcinomas. Further study made with 32 F31 rats killed at the age of five months revealed that hepatitis occurred in all of these rats.
Genetic analysis performed by various crosses of LEC and LEJ rats confirmed the previous result that hereditary hepatitis was caused by a single autosomal recessive gene. F1 hybrid rats never developed hepatitis, showing normal histology of the liver. Histological features of hepatitis in F2 (F1×1) and backcross (F1×LEC) rats were the same as those observed in the LEC rats. The preneoplastic foci also appeared in some of these hybrid rats at the age of eight months. We propose a gene symbol hts to designate the present hepatitis which is assumed to be homozygous in LEC strain rats.