UDP-glucuronosyltransferase activities were induced spontaneously during the development of
hepatitis in LEC (Long Evans Cinnamon-like coat color) rats. Transition of hepatic microsomal
UDP-glucuronosyltransferase activities was observed during the development of the LEC rat, which displayed spontaneous
fulminant hepatitis with severe
jaundice at about 12-16 weeks after birth.
UDP-glucuronosyltransferase activities toward various substrates in 8-week-old LEC and LEA (Long Evans Agouti coat color; control) rats were similar. After 8 weeks of age, the
transferase activities of LEA rats towards all substrates tested, except for
bilirubin, decreased slightly during the next 24 weeks. In LEC rats, the
transferase activities towards
serotonin and several phenolic
xenobiotics, such as
4-nitrophenol,
1-naphthol and
4-methylumbelliferone, but not
4-hydroxybiphenyl, increased about 2-fold at 16 weeks of age. During the 24 weeks following the first 8 weeks of age, the high level activities towards the
xenobiotics continued, with the exception of
bilirubin transferase activity which decreased gradually. These results suggest that a form of
UDP-glucuronosyltransferase, which catalyzes the glucuronidations of
serotonin and these
xenobiotics except for
4-hydroxybiphenyl, is induced during the development of
hepatitis in the LEC rat.