Presence of protein-bound unconjugated bile acids in the cytoplasmic fraction of rat brain.
Using liquid chromatography/electrospray ionization mass spectrometry, we have found three unconjugated bile acids [cholic acid (CA), chenodeoxycholic acid (CDCA), and deoxycholic acid (DCA)] in the rat brain cytoplasmic fraction. CDCA was detected only upon extraction with high concentrations of guanidine, indicating that it is bound noncovalently to protein in the brain. The most abundant of the three, it was present at a concentration of 1.6 nmol/g wet weight (approximately 15 mg of protein) of brain, corresponding to almost 30 times its serum concentration. CA and DCA were present at 1/30th the concentration of CDCA. Bile acids conjugated with amino acids, sulfuric acid, and glucuronic acid were not detected. These data clearly demonstrate that unconjugated CDCA and, to a lesser extent, CA and DCA, exists in the rat brain.
Mano
Nariyasu
N
Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai 980-8578, Japan. n-mano@mail.pharm.tohoku.ac.jp
Goto
Takaaki
T
Uchida
Masashi
M
Nishimura
Koji
K
Ando
Masayuki
M
Kobayashi
Norihiro
N
Goto
Junichi
J
D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism*; D001921:Brain / Q000378:metabolism* / Q000648:ultrastructure; D001923:Brain Chemistry; D003593:Cytoplasm / Q000378:metabolism*; D005260:Female; D008297:Male; D051381:Rats; D021241:Spectrometry, Mass, Electrospray Ionization
D001647:Bile Acids and Salts