Search results for "REDUCTASE"
showing 10 items of 798 documents
Metabolism of apigenin by rat liver phase I and phase II enzymes and by isolated perfused rat liver
2004
The metabolism of apigenin, a low estrogenic flavonoid phytochemical, was investigated in rat using liver models both in vitro (subcellular fractions) and ex vivo (isolated perfused liver). In vitro, phase I metabolism led to the formation of three monohydroxylated derivatives: luteolin which was the major metabolite (K(m) = 22.5 +/- 1.5 microM; V(max) = 5.605 +/- 0.090 nmol/min/mg protein, means +/- S.E.M.), scutellarein, and iso-scutellarein. These oxidative pathways were mediated by cytochrome P450 monooxygenases (P450s). The use of P450 inhibitors and inducers showed that CYP1A1, CYP2B, and CYP2E1 are involved. In vitro studies of phase II metabolism indicated that apigenin underwent co…
Different impacts of cardiovascular risk factors on oxidative stress.
2011
The objective of the study was to evaluate oxidative stress (OS) status in subjects with different cardiovascular risk factors. With this in mind, we have studied three models of high cardiovascular risk: hypertension (HT) with and without metabolic syndrome, familial hypercholesterolemia (FH) and familial combined hyperlipidemia (FCH) with and without insulin resistance. Oxidative stress markers (oxidized/reduced glutathione ratio, 8-oxo-deoxyguanosine and malondialdehide) together with the activity of antioxidant enzyme triad (superoxide dismutase, catalase, glutathione peroxidase) and activation of both pro-oxidant enzyme (NAPDH oxidase components) and AGTR1 genes, as well as antioxidant…
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…
ALDH1A3 Mutations Cause Recessive Anophthalmia and Microphthalmia
2013
Anophthalmia and microphthalmia (A/M) are early-eye-development anomalies resulting in absent or small ocular globes, respectively. A/M anomalies occur in syndromic or nonsyndromic forms. They are genetically heterogeneous, some mutations in some genes being responsible for both anophthalmia and microphthalmia. Using a combination of homozygosity mapping, exome sequencing, and Sanger sequencing, we identified homozygosity for one splice-site and two missense mutations in the gene encoding the A3 isoform of the aldehyde dehydrogenase 1 (ALDH1A3) in three consanguineous families segregating A/M with occasional orbital cystic, neurological, and cardiac anomalies. ALDH1A3 is a key enzyme in the…
Modification of hepatic drug-metabolizing enzymes in rat fed naturally occurring allyl sulphides
1994
1. The effects of feeding allyl sulphides to rat (2000 ppm of the diet for 15 days) were investigated on various microsomal hepatic drug-metabolizing enzymes by their immunochemical detection and catalytic activity. 2. Allyl sulphides provoked a temporary dietary restriction, which enhanced the microsomal level of P450 and the activities of NADH-cytochrome c reductase and p-hydroxybiphenyl UDP-glucuronyltransferase (UDPGT 2), and lowered the activities of p-nitrophenol hydroxylase (PNPH), N-nitrosodimethylamine demethylase (NDMAD), laurate omega-hydroxylase (LAH) and glutathione S-transferase (GST). Therefore, pair-fed animals were used as a more relevant control for the dietary effects of …
Measurement of substrate-induced oxygen uptake during microsomal drug oxidation using a gold micro-electrode.
1975
1. A resin-coated gold micro-electrode has been used for polarographic determination of oxygen concentration in liver microsomal suspensions from phenobarbital-pretreated rats. 2. The rate of oxygen uptake on addition of an NADPH-regenerating system and the rate after addition of various substrates of the mixed function oxidase system were measured. The rate of oxygen uptake was faster in the presence of substrate than in the presence of NADPH alone. 3. Kinetic constants (Km and V max) for biphenyl, hexobarbital, ethylmorphine, naphthalene and SKF 525-A measured by this technique compare favourably with those obtained either by measurements of NADPH oxidation, or chemical measurements of su…
Inhibition of ethoxyresorufin deethylase activity by natural flavonoids in human and rat liver microsomes
1990
Several flavones and flavonols (chrysin, quercetin, luteolin, flavone and 7, 8-benzoflavone) were found to inhibit ethoxyresorufin deethylase (EROD) activity in human and rat liver microsomes. In man, molecules without hydroxyl groups are more powerful inhibitors than polyhydroxylated flavonoids (7, 8-benzoflavone greater than flavone greater than chrysin greater than luteolin greater than quercetin greater than morin). In rat, chrysin was the strongest inhibitor and the less effective were morin and 7,8-benzoflavone. For all molecules human microsomes were more sensitive than rat microsomes. The most important difference concerned 7,8-benzoflavone which was 10,000-fold more potent in man.
Differential localization of neuronal nitric oxide synthase immunoreactivity and NADPH-diaphorase activity in the cat spinal cord.
1994
The distributions of neuronal nitric oxide synthase immunoreactivity (NOS-IR) and NADPH-diaphorase (NADPH-d) activity were compared in the cat spinal cord. NOS-IR in neurons around the central canal, in superficial laminae (I and II) of the dorsal horn, in the dorsal commissure, and in fibers in the superficial dorsal horn was observed at all levels of the spinal cord. In these regions, NOS-IR paralleled NADPH-d activity. The sympathetic autonomic nucleus in the rostral lumbar and thoracic segments exhibited prominent NOS-IR and NADPH-d activity, whereas the parasympathetic nucleus in the sacral segments did not exhibit NOS-IR or NADPH-d activity. Within the region of the sympathetic autono…
Prothrombotic gene variants as risk factors of acute myocardial infarction in young women
2012
Abstract Background Acute myocardial infarction (AMI) in young women represent an extreme phenotype associated with a higher mortality compared with similarly aged men. Prothrombotic gene variants could play a role as risk factors for AMI at young age. Methods We studied Factor V Leiden, FII G20210A, MTHFR C677T and beta-fibrinogen -455G>A variants by real-time PCR in 955 young AMI (362 females) and in 698 AMI (245 females) patients. The data were compared to those obtained in 909 unrelated subjects (458 females) from the general population of the same geographical area (southern Italy). Results In young AMI females, the allelic frequency of either FV Leiden and of FII G20210A was signif…
On the spectral intermediate at 440 nm formed during mixed function substrate oxidation.
1974
Abstract The spectral shoulder formed at 440 nm in microsomes oxidising hexobarbital and other drugs has been investigated and some of its properties characterised. Hexobarbital, pentobarbital, ethylmorphine and barbital produce this shoulder, while acetanilide, aniline, desmethylimipramine, imipramine, metyrapone and SKF 525-A do not. The formation of the 440 nm shoulder depends on the presence of NADPH and oxygen and is reduced in size when NADH is also present. At saturating substrate concentrations the size of the 440 nm shoulder is correlated to the cytochrome P-450 content. The hexobarbital induced shoulder can be inhibited by drug metabolism inhibitors such as metyrapone, imipramine …