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Cloning of the dog bile salt export pump (BSEP; ABCB11) and functional comparison with the human and rat proteins
Author(s) -
Yabuuchi Hikaru,
Tanaka Kenji,
Maeda Miyako,
Takemura Masaaki,
Oka Masaki,
Ohashi Rikiya,
Tamai Ikumi
Publication year - 2008
Publication title -
biopharmaceutics and drug disposition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 58
eISSN - 1099-081X
pISSN - 0142-2782
DOI - 10.1002/bdd.629
Subject(s) - bile salt export pump , taurocholic acid , troglitazone , chemistry , clofibrate , bile acid , biochemistry , glycocholic acid , pravastatin , biology , transporter , endocrinology , medicine , gene , cholesterol , peroxisome proliferator activated receptor , cholic acid
Abstract The dog bile salt export pump (BSEP; ABCB11) was cloned and expressed in a Sf9 insect cell system. The deduced amino acid sequence encodes a 1325‐amino‐acid protein, which shows 89.4% and 80.2% homology with human BSEP and rat Bsep, respectively. The transcript of the dog Bsep gene was detected at a high level in liver, but not other tissues, by quantitative RT‐PCR. The BSEP‐expressing membrane vesicles isolated from Sf9 cells exhibited saturable uptake of [ 3 H]taurocholic acid with Michaelis constants ( K m ) of 33.7, 22.2 and 19.9 µM for the dog, rat and human transporters, respectively. The uptake of [ 3 H]taurocholic acid by all three transporters was significantly inhibited by troglitazone, glibenclamide, and other several inhibitors, while pravastatin inhibited dog Bsep and human BSEP, but not rat Bsep at 100 µM. The IC 50 of troglitazone for dog Bsep, human BSEP, and rat Bsep were 32, 20, and 60 µM, and those of pravastatin were 441, 240 and >1,000 µM, respectively. In conclusion, while dog Bsep shows similar ATP‐dependent bile acid transport characteristics to human BSEP and rat Bsep, there is a species difference in affinity for drugs such as pravastatin and troglitazone. Copyright © 2008 John Wiley & Sons, Ltd.