Search results for "Transferase"
showing 10 items of 1030 documents
Transcription of the MAT2A gene, coding for methionine adenosyltransferase, is up-regulated by E2F and Sp1 at a chromatin level during proliferation …
2006
Methionine adenosyltransferase (MAT) is an essential enzyme because it catalyzes the formation of S-adenosylmethionine, the main methyl donor. Two MAT-encoding genes (MAT1A, MAT2A) are found in mammals. The latter is expressed in proliferating liver, dedifferentiation and cancer, whereas MAT1A is expressed in adult quiescent hepatocytes. Here, we report studies on the molecular mechanisms controlling the induction of MAT2A in regenerating rat liver and in proliferating hepatocytes. The MAT2A is up-regulated at two discrete moments during liver regeneration, as confirmed by RNApol-ChIP analysis. The first one coincides with hepatocyte priming (i.e. G0-G1 transition), while the second one tak…
Fatty acid oxidation and related gene expression in heart depleted of carnitine by mildronate treatment in the rat.
2004
The metabolic and genic effects induced by a 20-fold lowering of carnitine content in the heart were studied in mildronate-treated rats. In the perfused heart, the proportion of palmitate taken up then oxidized was 5-10% lower, while the triacylglycerol (TAG) formation was 100% greater than in controls. The treatment was shown to increase the maximal capacity of heart homogenates to oxidize palmitate, the mRNA level of carnitine palmitoyltransferase I (CPT-I) isoforms, the specific activity of CPT-I in subsarcolemmal mitochondria and the total carnitine content of isolated mitochondria. Concomitantly, the increased mRNA expression of lipoprotein lipase, fatty acid translocase and enzymes of…
Glucagon-like peptide-1 modulates neurally evoked mucosal chloride secretion in guinea pig small intestine in vitro
2011
Glucagon-like peptide-1 (GLP-1) acts at the G protein-coupled receptor, GLP-1R, to stimulate secretion of insulin and to inhibit secretion of glucagon and gastric acid. Involvement in mucosal secretory physiology has received negligible attention. We aimed to study involvement of GLP-1 in mucosal chloride secretion in the small intestine. Ussing chamber methods, in concert with transmural electrical field stimulation (EFS), were used to study actions on neurogenic chloride secretion. ELISA was used to study GLP-1R effects on neural release of acetylcholine (ACh). Intramural localization of GLP-1R was assessed with immunohistochemistry. Application of GLP-1 to serosal or mucosal sides of fla…
Beneficial effects of dithiothreitol on relative levels of glutathione S-transferase activity and thiols in oocytes, and cell number, DNA fragmentati…
2006
We analyzed the effect of in vitro aging of mouse oocytes in the presence of dithiothreitol (DTT) on relative levels of glutathione S-transferase (GST) activity and thiols in oocytes, and cell number, DNA fragmentation and cellular allocation to the inner cell mass (ICM) and trophectoderm (TE) lineage at the blastocyst stage. Ovulated oocytes from gonadotropin primed hybrid female mice of 6-8 weeks of age were aged in vitro in the presence of 0, 5, 50, or 500 microM DTT for 6 hr prior to insemination. Relative levels of GST activity and thiols in oocytes were determined by confocal laser scanning microscopy, DNA fragmentation using a single-step TUNEL method, and cell allocation to the ICM …
Chronic stress induces changes in the structure of interneurons and in the expression of molecules related to neuronal structural plasticity and inhi…
2011
Chronic stress in experimental animals, one of the most accepted models of chronic anxiety and depression, induces structural remodeling of principal neurons in the amygdala and increases its excitation by reducing inhibitory tone. These changes may be mediated by the polysialylated form of the neural cell adhesion molecule (PSA-NCAM), a molecule related to neuronal structural plasticity and expressed by interneurons in the adult CNS, which is downregulated in the amygdala after chronic stress. We have analyzed the amygdala of adult mice after 21 days of restraint stress, studying with qRT-PCR the expression of genes related to general and inhibitory neurotransmission, and of PSA synthesizi…
Properties of the microsomal and cytosolic glutathione transferases involved in hexachloro-1:3-butadiene conjugation
1989
Hexachloro-1,3-butadiene (HCBD) is a substrate for the hepatic microsomal glutathione transferases and is metabolised at higher rates by these enzymes than their cytosolic counterparts. Conjugation reactions catalysed by the microsomal and cytosolic transferases have been studied and characterized using this substrate and 1-chloro-2,4-dinitrobenzene (CDNB). In rat liver microsomes the Km values for HCBD and CDNB were 0.91 and 0.012 mM and in cytosol 0.51 and 0.10 mM respectively. Vmax values for HCBD were 1.39 and 0.35 nmol conjugate formed/min/mg protein for microsomes and cytosol respectively. In microsomal systems HCBD was a potent competitive inhibitor of the metabolism of CDNB with a K…
Biallelic pathogenic variants in the lanosterol synthase gene LSS involved in the cholesterol biosynthesis cause alopecia with intellectual disabilit…
2019
International audience; Purpose Lanosterol synthase (LSS) gene was initially described in families with extensive congenital cataracts. Recently, a study has highlighted LSS associated with hypotrichosis simplex. We expanded the phenotypic spectrum of LSS to a recessive neuroectodermal syndrome formerly named alopecia with mental retardation (APMR) syndrome. It is a rare autosomal recessive condition characterized by hypotrichosis and intellectual disability (ID) or developmental delay (DD), frequently associated with early-onset epilepsy and other dermatological features. Methods Through a multicenter international collaborative study, we identified LSS pathogenic variants in APMR individu…
Induction of rat liver microsomal epoxide hydrolase by its endogenous substrate 16α, 17α-epoxyestra-1,3,5-trien-3-ol
1995
1. The influence of the endogenous steroid epoxides 16 alpha, 17 alpha-epoxyestra-1,3,5(10)-trien-3-ol (estroxide) and 16 alpha, 17 alpha-expoxiandrost-4-en-3-one (androstene oxide) and their metabolic precursors estra-1,3,5(10), 16-tetraen-3-ol (estratetraenol) and androsta-4, 16-dien-3-one (androstadienone) on the specific activities of hepatic microsomal and soluble epoxide hydrolase, glutathione S-transferase, dihydrodiol dehydrogenase, and 7-ethoxycoumarin deethylase was investigated in the male Sprague-Dawley rat. 2. Both estroxide and estratetraenol induced microsomal epoxide hydrolase activity towards styrene oxide and estroxide itself 2-2.5-fold and glutathione conjugation of 1-chl…
Regulation of glutathione metabolism in Ehrlich ascites tumour cells.
1992
Glutathione metabolism was studied in cancer cells during the growth of an Ehrlich ascites tumour. GSH, but not GSSG, content decreases when cell proliferation and the rate of protein synthesis in the tumour decrease. This change correlates with a decrease in the rate of GSH synthesis and an increase in glutathione peroxidase and glutathione S-transferase activities. Glutathione efflux from tumour cells seems to co-ordinate with the rate of GSH synthesis. Cysteine, and not methionine, promotes GSH synthesis in tumour cells. However, changes in the rate of GSH synthesis are not due to limitations in the supply of blood cysteine or to changes in the intracellular amino acid pool of the cancer…
Expression ofDNMT3A transcripts and nucleolar localization of DNMT3A protein in human testicular and fibroblast cells suggest a role for de novo DNA …
2006
Transcriptional silencing during differentiation of human male germ cells and serum starvation of human fibroblasts is controlled by epigenetic mechanisms that involve de novo DNA methylation. It is associated with high expression of different transcripts of the DNA methyltransferase 3A (DNMT3A) gene that encode two isoforms with de novo methyltransferase activity and one without catalytic activity. Western blots revealed that DNMT3A protein (with catalytic domain) is present at low levels in several tissues and at increased levels in testicular cells and growth-arrested fibroblasts. Immunofluorescence experiments localized DNMT3A to discrete nucleolar foci in B spermatogonia and resting fi…