title: Rat liver and kidney catechol-O-methyltransferase activity measured by high-performance liquid chromatography with fluorescence detection.
abstract: We have previously reported a highly sensitive method for the measurement of catechol-O-methyltransferase (COMT) activities in rat erythrocytes with norepinephrine (NE), an endogenous native substrate, using high-performance liquid chromatography (HPLC)-fluorescence or peroxyoxalate chemiluminescence reaction detection. Applying this method to COMT activities in rat liver and kidney, known to have the highest activities of all organs, the optimum reaction conditions were investigated. Under the optimum conditions, soluble (S)-COMT and membrane-bound (MB)-COMT activities in rat liver, with NE as a substrate, were 2.17 +/- 0.33 and 0.16 +/- 0.02 nmol/min/mg protein (n = 5), respectively. In rat kidney, S-COMT and MB-COMT activities were 1.81 +/- 0.20 and 0.079 +/- 0.009 nmol/min/mg protein (n = 5), respectively. Since liver and kidney play important roles in inactivating catecholamines, using the proposed method would yield critical information to delineate the role of metabolism of catecholamines in rat tissues.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Tsunoda
authors.forename: Kazuko
authors.initials: K
authors.lastname: Takezawa
authors.forename: Mayumi
authors.initials: M
authors.lastname: Masuda
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Imai
mesh_terms: D000818:Animals; D002394:Catechol O-Methyltransferase / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D002394:Catechol O-Methyltransferase; D009638:Norepinephrine