Studies on the metabolic fate of M17055, a novel diuretic (4): species difference in metabolic pathway and identification of human CYP isoform responsible for the metabolism of M17055

The metabolic profile of M17055, a novel diuretic, after administration to experimental animals and after incubation with human liver microsomes was investigated. 1. Extensive metabolism was observed in rats and monkeys and the structures of six metabolites (RU1, RU2, and RU3 from rat urine or liver perfusate; MU1, MU2 and MU3 from monkey urine) were assumed or identified. The clear species difference of metabolism was revealed between rats and a monkey with different structures of the isolated metabolites. 2. When these metabolites were quantified using radioactive material, RU3, RU1 and MU3 were considered to be major metabolites in rat urine, rat bile and monkey urine respectively, while in a dog, unchanged drug was observed as the major component indicating only little metabolism occurred in dog, when administered intravenously. 3. RU1 and RU2 were also generated from [(14)C]M17055 after incubation with human liver microsomes, suggesting that the metabolic pathway of M17055 in humans involves that observed in rats. 4. [(14)C]M17055 metabolism in human liver microsomes was inhibited by CYP2C8/9 and CYP3A4/5 inhibitors, and also by the antibodies that recognize CYP2C8/9/19 and CYP3A4. Significant correlations were observed between the rate of [(14)C]M17055 metabolism and the activity of testosterone 6beta-hydroxylation or tolbutamide methyl-hydroxylation. cDNA-expressed CYP3A4 and CYP2C9 could catalyze the metabolism of [(14)C]M17055. These results suggest that the metabolism of M17055 in human liver microsomes is catalyzed mainly by CYP3A4 and CYP2C9.     

Eleven novel single nucleotide polymorphisms in the NR1I2 (PXR) gene, four of which induce non-synonymous amino acid alterations

Eleven novel single nucleotide polymorphisms (SNPs) were found in the NR1I2 (PXR/SXR) gene from 205 Japanese subjects. The detected SNPs were as follows: 1) SNP, MPJ6_1I2001; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-TTTCTACCTCTAC/TTATTGAAAGGGC-3'. 2) SNP, MPJ6_1I2004; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-AGGCCCAAATGTG/AAGTGATGCATAG-3'. 3) SNP, MPJ6_1I2007; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-TGCCAGGCCTGCC/TGCCTGCGCAAGT-3'. 4) SNP, MPJ6_1I2008; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-GAGTGAGCAGTGG/CGCGCGCGGGCGG-3'. 5) SNP, MPJ6_1I2010; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-CAGAGGAGCAGCG/AGATGATGATCAG-3'. 6) SNP, MPJ6_1I2011; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-CTGGAAGTGGCCA/GGGAGGTTCAAAG-3'. 7) SNP, MPJ6_1I2013; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-TCTTCCTCTCGCC/TCCCAACTTCTGG-3'. 8) SNP, MPJ6_1I2017; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-ATTGAATGCAATC/TGGCCCCAGCCTG-3'. 9) SNP, MPJ6_1I2018; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-GGTGAGCACAGCA/GGGGGGTGAGGAC-3'. 10) SNP, MPJ6_1I2019; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-GAGCTCCGCAGCA/GTCAATGCTCAGC-3'. 11) SNP, MPJ6_1I2021; GENE NAME, NR1I2; ACCESSION NUMBER, AF364606; LENGTH, 25 bases; 5'-GGTGACACCTCCG/AAGAGGCAGCCAG-3'. The frequencies were 0.0293 for MPJ6_1I2021, 0.0073 for MPJ6_1I2011, and 0.0024 for the other 9 SNPs. All SNPs were found as heterozygous. Among these SNPs, MPJ6_1I2007, MPJ6_1I2010, MPJ6_1I2017 and MPJ6_1I2019 induce non-synonymous amino acid alterations (R98C, R148Q, R381W and I403V, respectively, in PAR1).     

Major cytochrome P450 enzymes responsible for microsomal aldehyde oxygenation of 11-oxo-Delta8-tetrahydrocannabinol and 9-anthraldehyde in human liver

Hepatic microsomes from human liver catalyzed oxidation of the allyl aldehydes such as 11-oxo-Delta(8)-tetrahydrocannabinol and 9-anthraldehyde to the corresponding carboxylic acid metabolites. The oxygenation mechanism was confirmed by GC-MS that molecular oxygen was exclusively incorporated into Delta(8)-tetrahydrocannabinol-11-oic acid and 9-anthracene carboxylic acid formed under oxygen-18 gas. The microsomal aldehyde oxygenase (named MALDO) activities of 11-oxo-Delta(8)-tetrahydrocannabinol and 9-anthraldehyde were significantly inhibited by the antibody against CYP2C and CYP3A, respectively. MALDO activity for 11-oxo-Delta(8)-tetrahydrocannabinol was significantly inhibited by sulfaphenazole whereas that for 9-anthraldehyde was markedly inhibited by troleandomycin, but not by sulfaphenazole. CYP2C9 expressed in human B-lymphoblastoid cells catalyzed efficiently the MALDO activity for 11-oxo-Delta(8)-tetrahydrocannabinol (10.1 nmol/min/nmol P450), while the catalytic activities of other human CYPs expressed in the cells were lesser extents. In MALDO activity for 9-anthraldehyde, CYP3A4 expressed in the cells had the highest catalytic activity (7.72 nmol/min/nmol P450). These results indicate that CYP2C9 and CYP3A4 are major enzymes responsible for the MALDO activity in human liver for 11-oxo-Delta(8)-tetrahydrocannabinol and 9-anthraldehyde, respectively.     

Nobiloside, a new neuraminidase inhibitory triterpenoidal saponin from the marine sponge Erylus nobilis

A neuraminidase inhibitor, nobiloside (1), was isolated from the marine sponge Erylus nobilis Thiele, 1903. Its structure was determined as a penasterol trisaccharide. The absolute configurations were determined by NMR and chiral GC analysis. It inhibited neuraminidase from the bacterium Clostridium perfringens with an IC50 value of 0.46 microg/mL.     

Inhibition of tumor-promoting effects by poricoic acids G and H and other lanostane-type triterpenes and cytotoxic activity of poricoic acids A and G from Poria cocos

The structures of two novel 3,4-seco-lanostane-type triterpenes isolated from the sclerotium of Poria cocos were established to be 16alpha-hydroxy-3,4-seco-lanosta-4(28),8,24-triene-3,21-dioic acid (1; poricoic acid G) and 16alpha-hydroxy-3,4-seco-24-methyllanosta-4(28),8,24(24(1))-triene-3,21-dioic acid (2; poricoic acid H) on the basis of spectroscopic methods. These two, and eight other known compounds isolated from the sclerotium, poricoic acid B (3), poricoic acid A (4), tumulosic acid (5), dehydrotumulosic acid (6), 3-epidehydrotumulosic acid (7), polyporenic acid C (8), 25-hydroxy-3-epidehydrotumulosic acid (9), and dehydroabietic acid methyl ester (10), showed potent inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Evaluation of the cytotoxicity of compounds 1 and 4 against human cancer cell lines revealed that 1 was significantly cytotoxic to leukemia HL-60 cells [GI(50) (concentration that yields 50% growth) value 39.3 nM], although it showed only moderate cytotoxicity to the other cells. Compound 4 exhibited moderate cytotoxicity to all of the cancer cell lines tested.     

Corticatic acids D and E,polyacetylenic geranylgeranyltransferase type I inhibitors,from the marine sponge Petrosia corticata

Two new polyacetylenic acids, corticatic acids D (2) and E (3), have been isolated from the marine sponge Petrosia corticata along with the known corticatic acid A (1) as geranylgeranyltransferase type I (GGTase I) inhibitors. Their structures were elucidated on the basis of spectroscopic and chemical methods. Compounds 1-3 inhibited GGTase I from Candida albicans with IC(50) values of 1.9-7.3 microM.     

Impaired acetylcholine-induced release of nitric oxide in the aorta of male aromatase-knockout mice: regulation of nitric oxide production by endogenous sex hormones in males

The consequences of estrogen deficiency on the cardiovascular system have been widely examined in females. The effects of endogenous estrogen deficiency in males are less clear. The aromatase-knockout (ArKO) mouse lacks a functional Cyp19 gene, which encodes aromatase, and is thus incapable of synthesizing endogenous estrogen. In the present study, we examined the effect of lack of endogenous estrogens on vascular function in aortic rings isolated from male ArKO mice and compared these effects to rings from wild-type (WT) littermates. Full concentration-response curves to norepinephrine, acetylcholine, isoprenaline, and sodium nitroprusside were obtained in the absence and presence of the nitric oxide synthase inhibitor Nomega-nitro-L-arginine in aortic segments set up in isometric myographs. Responses to noradrenaline were not different in aorta from ArKO compared with WT mice. Both Nomega-nitro-L-arginine and endothelium denudation significantly shifted the noradrenaline concentration-response curve to the left; however, this shift was not different in ArKO compared with WT. Responses to the endothelium-dependent vasodilator acetylcholine were significantly blunted in aortic rings from ArKO mice (Emax, 58.2+/-0.9% and 34.0+/-0.5% in wild-type and ArKO, respectively; P<0.05), whereas responses to the endothelium-independent agonist sodium nitroprusside and to the partial endothelium-dependent agonist isoprenaline were not affected. These findings suggest that endogenous estrogen facilitate vasorelaxation in males. This may be via modulating endothelial function rather than vascular smooth muscle cell responsiveness.     

Neuroradiological study of patients with amyotrophic lateral sclerosis and parkinsonism-dementia complex on the Kii peninsula of Japan

BACKGROUND: The Kii peninsula of Japan, together with Guam and West New Guinea, has one of the highest incidences of amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC) in the world. OBJECTIVE: To perform neuroimaging studies on patients with ALS and PDC on the Kii peninsula. METHODS: Results of computed tomography, magnetic resonance imaging, and single-photon emission computed tomography were studied in 4 patients with ALS and in 10 patients with PDC from the Hohara village on the Kii peninsula of Japan. RESULTS: In patients with PDC, there was mild to severe atrophy of the frontal and temporal lobes on computed tomography and magnetic resonance imaging and a marked decrease in cerebral blood flow on single-photon emission computed tomography. In contrast, in patients with ALS, there was a decrease in cerebral blood flow of the frontal and temporal lobes, although the patients did not show signs of clinical dementia or obvious brain atrophy on computed tomography or magnetic resonance imaging. CONCLUSION: The finding of an obvious decrease in cerebral blood flow of the frontal and temporal lobes in patients with PDC and ALS with or without cerebral atrophy supports the concept that the 2 conditions are different manifestations of a single frontotemporal tauopathy.     

Demographic and psychological features of déjà vu experiences in a nonclinical Japanese population

The authors investigated the frequency and correlates of déjà vu experiences in 386 healthy adult volunteers recruited from several areas in Japan. Déjà vu experiences and related experiences were evaluated using the Inventory of Déjà vu Experiences Assessment. Déjà vu experiences were observed by 294 (76.2%) of the 386 participants. Persons who experienced déjà vu were younger and more educated than persons who had not experienced it. There were no differences in the frequency of déjà vu experiences based on sex, hand preference, or area of residence. Subsequent factor analysis associated déjà vu with precognitive dreams and remembering dreams as dream- and memory-related factors rather than with the dissociation-related factors of depersonalization, derealization, jamais vu, and daydreams or with mental activity-related factors such as paranormal quality and travel frequency. Results suggest that déjà vu experiences are associated with good memory function.     

Anaphylaxis due to burdock

A 53‐year‐old Japanese man, with a history of developing urticaria (once after consuming mackerel and 10 times after consuming boiled burdock, carrot, curry, and rice), presented with redness over his entire body and dyspnea 1 h after eating boiled burdock. Physical examination revealed a low blood pressure of 64/29 mmHg and stridor, together with striking redness of the whole body; he was diagnosed to be in anaphylactic shock. He recovered from the anaphylactic shock with subcutaneous injection of epinephrine (1 mg) and an intravenous drip of lactate Ringer's solution containing hydrocortisone (100 mg) and dexamethasone (8 mg). Laboratory examination and skin prick test were performed 3 weeks after his first visit. The total immunoglobulin E (radioimmunosobent test) level was 190 IU/mL, and specific immunoglobulin E for mackerel and carrot was found to be negative. Skin prick test was performed on the volar forearm with burdock, carrot, and turmeric after he had not taken any medication for 1 week. It was also conducted in normal healthy persons at the same time. A skin prick was made with a PRICK‐LANCETTER® (made in Sweden) using 1% histamine chloride solution and 0.9% saline solution as positive (3+) and negative (–) controls, respectively. For skin prick tests, burdock and carrot were employed in their boiled and raw conditions. Turmeric powder was diluted to 1% and 10% in petrolatum. Skin prick tests were judged according to the recommendations of the European Academy of Allergy and Clinical Immunology (Shono M. The skin test learned in Finland. Hifubyou‐Shinryoh 1999; 25 (3) : 255–269; Bernstein IL. Proceedings of the task force on guidelines for standardizing old and new technologies used for the diagnosis and treatment of allergic diseases. J Allergy Clin Immunol 1988; 82: 487–526). The results of the skin prick tests ( Table 1 ) were positive for raw and boiled burdock and carrot, but negative for turmeric ( Fig. 1 ). Two normal healthy controls showed negative responses to all substances.

Table 1. Results of skin prick test