[Relationship between the increase of hepatic D-bifunctional protein activity and bile acid biosynthesis in rats].
OBJECTIVE
To determine the physiological role of D-bifunctional protein (DBP) in bile acid biosynthesis through investigating the effect of increasing activity of DBP on bile acid biosynthesis.


METHODS
Twenty male Wistar rats were divided into two groups: diethylhexyl phthalate (DEHP) group (n = 10) and control group (n = 10). Serum triglyceride, total cholesterol, hepatic DBP activity, and fecal bile acids were assayed. The mRNA levels of hepatic peroxisome proliferator-activated receptor alpha (PPARalpha), DBP, and cholesterol 7alpha-hydroxylase (CYP7A1) were detected by RT-PCR.


RESULTS
Compared with control group, serum triglyceride level was decreased significantly and PPARalphamRNA level was increased significantly in DEHP group (P < 0.01). Together with a sharp induction of DBP mRNA expression and DBP activity in DEHP group (P < 0.01), the levels of CYP7A1 mRNA and fecal bile acids were significantly increased by 1.9 times and 1.6 times respectively compared to control group (P < 0.01). There was a significantly positive correlation between DBP mRNA level or DBP activity and CYP7A1 mRNA level (r = 0.89, P < 0.01; r = 0.95, P < 0.01).


CONCLUSIONS
The up-regulation of DBP mRNA and activity in liver can result in the increase in CYP7A1 mRNA expression and bile acid biosynthesis, suggesting that DBP may be involved in bile acid biosynthesis together with CYP7A1.
Shi
Ru-ling
RL
Department of Biochemistry, Hebei Medical University, Shijiazhuang 050017, China.
Zhao
Chao-xian
CX
Zhu
Hai-bao
HB
Yang
Yuan
Y
Wang
Su-ling
SL
Jiang
Ling-ling
LL
D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000818:Animals; D001647:Bile Acids and Salts / Q000096:biosynthesis*; D002790:Cholesterol 7-alpha-Hydroxylase / Q000032:analysis; D004746:Enoyl-CoA Hydratase / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism*; D047493:PPAR alpha / Q000032:analysis; D064029:Peroxisomal Multifunctional Protein-2; D012333:RNA, Messenger / Q000032:analysis; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
D001647:Bile Acids and Salts; D009097:Multienzyme Complexes; D047493:PPAR alpha; D012333:RNA, Messenger; D015067:17-Hydroxysteroid Dehydrogenases; C491286:Hsd17b4 protein, rat; D002790:Cholesterol 7-alpha-Hydroxylase; D064029:Peroxisomal Multifunctional Protein-2; D004746:Enoyl-CoA Hydratase