RT Journal Article SR Electronic T1 Interindividual Variability of Carboxymethylenebutenolidase Homolog, a Novel Olmesartan Medoxomil Hydrolase, in the Human Liver and Intestine JF Drug Metabolism and Disposition JO Drug Metab Dispos FD American Society for Pharmacology and Experimental Therapeutics SP 1156 OP 1162 DO 10.1124/dmd.113.051482 VO 41 IS 5 A1 Ishizuka, Tomoko A1 Rozehnal, Veronika A1 Fischer, Thomas A1 Kato, Ayako A1 Endo, Seiko A1 Yoshigae, Yasushi A1 Kurihara, Atsushi A1 Izumi, Takashi YR 2013 UL http://dmd.aspetjournals.org/content/41/5/1156.abstract AB Olmesartan medoxomil (OM) is a prodrug-type angiotensin II type 1 receptor antagonist. OM is rapidly converted into its active metabolite olmesartan by multiple hydrolases in humans, and we recently identified carboxymethylenebutenolidase homolog (CMBL) as one of the OM bioactivating hydrolases. In the present study, we further investigated the interindividual variability of mRNA and protein expression of CMBL and OM-hydrolase activity using 40 individual human liver and 30 intestinal specimens. In the intestinal samples, OM-hydrolase activity strongly correlated with the CMBL protein expression, clearly indicating that CMBL is a major contributor to the prodrug bioactivation in human intestine. The protein and activity were highly distributed in the proximal region (duodenum and jejunum) and decreased to the distal region of the intestine. Although there was high interindividual variability (16-fold) in both the protein and activity in the intestinal segments from the duodenum to colon, the interindividual variability in the duodenum and jejunum was relatively small (3.0- and 2.4-fold, respectively). In the liver samples, the interindividual variability in the protein and activity was 4.1- and 6.8-fold, respectively. No sex differences in the protein and activity were shown in the human liver or intestine. A genetically engineered Y155C mutant of CMBL, which was caused by a single nucleotide polymorphism rs35489000, showed significantly lower OM-hydrolase activity than the wild-type protein although no minor allele was genotyped in the 40 individual liver specimens.