Mice that are homozygous for the mutation are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. Screening of third generation mice (G3) on standard chow identified a 20 week old male with an increased blood urea nitrogen (BUN) of 34 mg/dL. Testing one week later confirmed the increased BUN value (35 mg/dL). This mutant mouse strain may be useful in studies of kidney function.
This phenotypic deviant was identified following multidose ethylnitrosourea (ENU) treatments to induce mutations in male founder C57BL/6J mice (Stock No. 000664), in complex heart, lung, blood, and sleep disorders at the Mouse Heart, Lung, Blood, and Sleep Disorders (HLBS) Center at The Jackson Laboratory. In the F2 and F3 generations, some animals exhibited increased albumin/creatinine ratios (ACR) in addition to increased BUN levels. In succeeding generations, mice with elevated BUN were bred away from mice with elevated ACR to establish the "B" line.