Hypothalamic ATF3 is involved in regulating glucose and energy metabolism in mice.

AIMS/HYPOTHESIS: The pancreas and hypothalamus are critical for maintaining nutrient and energy homeostasis, and combined disorders in these organs account for the onset of the metabolic syndrome. Activating transcription factor 3 (ATF3) is an adaptive response transcription factor. The physiological role of ATF3 in the pancreas has been controversial, and its role in the hypothalamus remains unknown. To elucidate the roles of ATF3 in these organs, we generated pancreas- and hypothalamus-specific Atf3 knockout (PHT-Atf3-KO) mice in this study. METHODS: We crossed mice bearing floxed Atf3 alleles with Pdx1-cre mice, in which cre is specifically expressed in the pancreas and hypothalamus, and analysed metabolic variables, pancreatic morphology, food intake, energy expenditure and sympathetic activity in adipose tissue. We also used a hypothalamic cell line to investigate the molecular mechanism by which ATF3 regulates transcription of the gene encoding agouti-related protein (Agrp). RESULTS: Although PHT-Atf3-KO mice displayed better glucose tolerance, neither plasma glucagon nor insulin level was altered in these mice. However, these mice exhibited higher insulin sensitivity, which was accompanied by a leaner phenotype due to decreased food intake and increased energy expenditure. We also observed decreased hypothalamic Agrp expression in PHT-Atf3-KO mice. Importantly, an increase in ATF3 levels is induced by fasting or low glucose in the hypothalamus. We also showed that ATF3 interacts with forkhead box-containing protein, O subfamily 1 (FoxO1) on the Agrp promoter and activates Agrp transcription. CONCLUSIONS/INTERPRETATION: Our results suggest that ATF3 plays an important role in the control of glucose and energy metabolism by regulating Agrp.

Treatment continuation rate in relation to efficacy and toxicity in long-term therapy with low-dose methotrexate, sulfasalazine, and bucillamine in 1,358 Japanese patients with rheumatoid arthritis.

OBJECTIVE: To evaluate the effectiveness of disease-modifying antirheumatic drugs, namely, methotrexate (MTX), sulfasalazine (SSZ) and bucillamine (BUC) at low-doses (4, 6 or 8 mg MTX, 500 or 1,000 mg SSZ, and 100 or 200 mg BUC) in 1,358 patients with a follow-up of at least 12 months and more than 120 months. METHODS: Clinical assessments were based on the number of painful joints (NPJ) and that of swollen joints (NSJ), CRP level, erythrocyte sedimentation rate, rheumatoid factor level and morning stiffness before and after treatment. Results were evaluated on the basis of the duration of treatment for each drug with inefficacy or inadequate efficacy as one endpoint for discontinuation and adverse drug reactions (ADRs) as the other in single agent and combination therapy. The incidence and nature of ADRs in single and combination treatment are described. RESULTS: The effects of MTX, SSZ and BUC on clinical parameters were monitored over the first three months, and in particular, NPJs and NSJs were found to decrease significantly during single agent MTX or BUC treatment over 108 months. CRP levels remained significantly improved for more than 120 months with MTX. In the single and combination long-term treatments, continuation rate with inefficacy or inadequate efficacy as the end point achieved for each of the treatments were 83.1% for MTX, 76.0% for BUC, 68.5% for SSZ, and in the case of the combination treatments, these rates were 83.3% for MTX + BUC and 71.0% for MTX+SSZ. Continuation rates using ADRs as the end point were 88% for SSZ, 79.6% for BUC and 79.4% for MTX. The incidences of ADRs for the various treatments were: MTX 22.2%, SSZ 11.0%, BUC 20.6%, MTX + BUC 30.0% and MTX + SSZ 31.2%. CONCLUSION: MTX showed the highest efficacy even though it was administrated at a low dose (6-8 mg), as a single agent or in combination with other treatment. However, in combination treatments, the continuous duration of treatment ending in ADRs as the end point were lower than those in single treatments with MTX, SSZ and BUC.

Chemical transformation of gilvocarcin V. Modification of the side-chain.

Gilvocarcin V was chemically transformed to alter its biological activities as well as its solubility by mainly focusing on the vinyl side chain. The oxirane and oxime derivatives showed slightly decreased in vivo antitumor activity, while the aminoethylmorpholine derivative turned out to be soluble in some organic solvents.

Molecular cloning of monkey liver cytochrome P-450 cDNAs: similarity of the primary sequences to human cytochromes P-450.

Three cDNAs coding for monkey cytochrome P-450 (P450) 2C, 2E and 3A (MKmp13, MKj1 and MKnf2, respectively) were isolated from a lambda gt11 cDNA library of a liver from a 3-methylcholanthrene (3MC)-treated crab-eating monkey, using cDNA fragments for human P450 2C, 2E and 3A as respective probes. MKmp13 and MKnf2 were 1901 and 2032 bp long, containing entire coding regions for polypeptides of 490 and 503 residues, respectively. The deduced N-terminal amino acid sequences of MKmp13 and MKnf2 were identical with those of P450-MK1 and P450-MK2, which had been purified from liver microsomes of untreated and polychlorinated biphenyl (PCB)-treated crab-eating monkeys, respectively. MKj1 was 1508 bp long, encoding a polypeptide of 449 residues, which is presumed to lack N-terminal 45 residues as compared with the sequence for human P450 2E1. Northern blot analysis indicated that monkey P450 2C, 2E and 3A mRNAs were expressed constitutively in monkey livers. P450 2E and 3A mRNAs were induced by both 3MC and PCB, while P450 2C mRNA was induced only by PCB. The deduced amino acid sequences of four monkey cytochrome P-450 cDNAs, including P450 1A1 (MKah1) which we isolated previously, were more than 92% identical with those of corresponding human cytochrome P-450 cDNAs.

Molecular cloning of monkey P450 1A1 cDNA and expression in yeast.

Monkey P450 1A1 cDNA (MKah1) was isolated from the lambda gt11 cDNA library of a liver from a 3-methylcholanthrene (3MC)-treated crab-eating monkey using a dog P450 1A1 cDNA fragment as a probe. MKah1 was 2453 bp long and contained an entire coding region for a polypeptide of 512 residues. The nucleotide and deduced amino acid sequences of MKah1 displayed 95% and 94% identity with those of the human P450 1A1 gene, respectively. Even in the 3' noncoding region, MKah1 showed 94% homology with human P450 1A1, whereas it showed less than 69% homology with other mammalian P450 1A1. Monkey P450 1A1 mRNA was not detectable in untreated livers, but was induced by polychlorinated biphenyl and 3MC. The expression plasmid (designated as pMKC-1) was constructed by introduction of the coding region of MKah1 into a yeast expression vector (pAM82) containing the promoter of acid phosphatase (APase). Northern blot analysis revealed that monkey P450 1A1 mRNA was expressed in yeast under the control of the APase promoter. Microsomes from yeast transformed by pMKC-1 catalyzed 7-ethoxycoumarin O-deethylation, benzo(a)pyrene hydroxylation and the mutagenic activation of 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ), 3-amino-1-methyl-5H-pyrido(4,3-b)-indole acetate (Trp-P-2) and 2-amino-6-methyldipyrido(1,2-a:3',2'-d)imidazole acetate (Glu-P-1).

Reactivity of methylazoxymethanol and its metabolites with nucleophilic centers of DNA bases: a semi-empirical NDDO molecular orbital study.

The NDDO semiempirical molecular orbital method (Kikuchi, 1977; Kikuchi and Maeda, 1977) was used to characterize the reactivities of methylazoxy-methanol (MAM) and its metabolites with DNA nucleophilic base sites. The physical association of MAM was found to occur at the guanine N7 and 06 atoms, while the ultimate alkylation reaction by MAM was predicted to occur at the guanine N7 atom more easily than at the 06 atom of guanine. These trends were also observed in the results for MAM metabolites, methylazoxy formaldehyde (MAF) and methyloazoxy carboxylic acid (MAA), and can explain the experimentally observed selectivity of MAM alkylation on DNA bases (Matsumoto and Higa, 1966; Schank and Magee, 1967). Although the methyldiazonium ion has the highest reactivity with the guanine N7 atom among the MAM metabolites, it is proposed that MAF is another candidate to react directly with the N7 atom of guanine.

Modeling the metabolic pathways of methylazoxymethanol: a semiempirical molecular orbital study.

The NDDO semiempirical molecular orbital method (Kikuchi, 1977; Kikuchi and Maeda, 1977) was used to model proposed nonenzymatic metabolic pathways for the decomposition of methazoxymethanol (MAM) to a methyldiazonium ion. It was found that the lowest transition path involved protonation of the azoxy oxygen atom to form a six-membered transition state structure which decomposes to the methyldiazonium ion, CH2O, and a hydroxyl ion. This metabolic pathway is consistent with models proposed by Druckrey and Lange (1972) and Miyadera (1975). The calculations also suggest that methylazoxyformaldehyde, an enzymatic product of MAM, may directly alkylate to nucleic acid base sites.