Species difference in cholesterol 7alpha-hydroxylase expression of rabbit and rat liver microsomes after bile duct ligation.
BACKGROUND
Bile duct ligation (BDL) produces a good animal model for investigation of the metabolic changes in obstructive jaundice. The aim of this study was to investigate the species difference in expression of cholesterol 7alpha-hydroxylase (7alpha-hydroxylase) in rabbits and rats after BDL.


METHODS
Ten male New Zealand white rabbits weighing 2.5-3 kg and 12 male Wistar strain rats weighing 250-300 g were used. Half the animals underwent BDL, and half were sham operated (Sham). The animals were sacrificed on day 5 after operation. The livers were harvested, and levels of mRNA and 7alpha-hydroxylase activity were determined. Concentrations of serum bilirubin and bile acids were also measured.


RESULTS
In BDL rats, the levels of mRNA were increased 30%, and 7alpha-hydroxylase activity was three times that of the Sham group. In BDL rabbits, however, these values were approximately 60 and 50% lower than the Sham group, respectively. Serum bile acid concentrations increased up to 13 times in BDL rabbits and 70 times in BDL rats over that of the Sham groups. Serum cholesterol and serum total bilirubin concentration also increased after BDL in both animals.


CONCLUSIONS
These results suggest that there is a species difference in the expression of 7alpha-hydroxylase after BDL in rabbits and rats and the reason for this difference is most likely pretranslational regulation.
Tanaka
Shun-Ichi
S
Department of Surgery 1, Miyazaki Medical College, Kiyotake, Miyazaki 889-1692, Japan.
Kinowaki
Mitsuru
M
Maeda
Yorio
Y
Nagatomo
Junji
J
Kai
Masa-Hiro
MH
Kondo
Kazu-Hiro
KH
Chijiiwa
Kazuo
K
D000818:Animals; D001647:Bile Acids and Salts / Q000097:blood; D001652:Bile Ducts / Q000601:surgery*; D001663:Bilirubin / Q000097:blood; D002784:Cholesterol / Q000097:blood; D002790:Cholesterol 7-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism*; D008026:Ligation; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D009994:Osmolar Concentration; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D013045:Species Specificity
D001647:Bile Acids and Salts; D012333:RNA, Messenger; D002784:Cholesterol; D002790:Cholesterol 7-alpha-Hydroxylase; D001663:Bilirubin