Search results for "Enzymologic"

Carboxyl nonsteroidal anti-inflammatory drugs are efficiently glucuronidated by microsomes of the human gastrointestinal tract.

2004

Limited studies have been carried out on the biotransformation of carboxyl nonsteroidal anti-inflammatory drugs (NSAIDs) in the liver. However, the role of the intestine in NSAID metabolism has not been investigated. In this report, the contribution of UDP-glucuronosyltransferases (UGTs) in the human gastrointestinal (GI) tract from five donors to the glucuronidation of the NSAIDs, RS-ketoprofen, S-naproxen, RS- and S-etodolac, was investigated. UGT activity and, for some donors, mRNA levels were evaluated. All NSAIDs were glucuronidated throughout the GI tract; however, glucuronidation was low in stomach and duodenum as compared to the remainder of the intestine. RT-PCR analysis demonstrat…

Raloxifene promotes prostacyclin release in human endothelial cells through a mechanism that involves cyclooxygenase-1 and -2

2005

Objective To examine the effects of raloxifene on prostacyclin production by human umbilical vein endothelial cells (HUVEC) and to shed light on the molecular details of that action. Design Cell culture for 4, 8, 16, 24, and 48 hours. Setting University research laboratory. Patient(s) Source of HUVEC. Intervention(s) Measurement of prostacyclin production and of protein levels and mRNA expression of cyclooxygenase (COX)-1 and -2. Main Outcome Measure(s) Prostacyclin production was measured by enzyme immunoassay, the mRNA expression of COX-1 was measured by quantitative real time-polymerase chain reaction, and the protein levels of COX-1 and -2 were measured by immunoblotting. Result(s) Ralo…

Effects of Long-Term Nitroglycerin Treatment on Endothelial Nitric Oxide Synthase (NOS III) Gene Expression, NOS III–Mediated Superoxide Production, …

2000

Abstract —Long-term nitroglycerin (NTG) treatment has been shown to be associated with cross-tolerance to endothelium-dependent vasodilators. It may involve increased production of reactive oxygen species (such as superoxide, O 2 ·− ) that rapidly inactivate the nitric oxide (NO) released from the endothelial cells. It remains to be elucidated, however, whether long-term treatment with NTG alters the activity and expression of the endothelial NO synthase (NOS III) and whether this enzyme can contribute to O 2 ·− formation. We studied the influence of long-term NTG treatment on the expression of NOS III as assessed by RNase protection assay and Western blot. Tolerance was measured ex vivo i…

Clinical implications ofCYP3Apolymorphisms

2006

Due to their enormous substrate spectrum CYP3A4, -3A5 and -3A7 constitute the most important drug-metabolising enzyme subfamily in humans. CYP3As are expressed predominantly, but not exclusively, in the liver and intestine, where they participate in the metabolism of 45 - 60% of currently used drugs and many other compounds such as steroids and carcinogens. CYP3A expression and activity vary interindividually due to a combination of genetic and nongenetic factors such as hormone and health status, and the impact of environmental stimuli. Over the past several years, genetic determinants have been identified for much of the variable expression of CYP3A5 and -3A7, but not for CYP3A4. Using th…

Protein Phosphorylation by Peroxisome Proliferators: Species-specific Stimulation of Protein Kinases and Its Role in PP-induced Transcriptional Activ…

1996

Characterization and transcription studies of a phytochelatin synthase gene from the solitary tunicate Ciona intestinalis exposed to cadmium.

2014

The major thiol-containing molecules involved in controlling the level of intracellular ROS in eukaryotes, acting as a nonenzymatic detoxification system, are metallothioneins (MTs), glutathione (GSH) and phytochelatins (PCs). Both MTs and GSH are well-known in the animal kingdom. PC was considered a prerogative of the plant kingdom but, in 2001, a phytochelatin synthase (PCS) gene was described in the nematode Caenorhabditis elegans; additional genes encoding this enzyme were later described in the earthworm Eisenia fetida and in the parasitic nematode Schistosoma mansoni but scanty data are available, up to now, for Deuterostomes. Here, we describe the molecular characteristics and transc…

Inhibition of small G proteins of the Rho family by statins orClostridium difficiletoxin B enhances cytokine-mediated induction of NO synthase II

2000

In order to investigate the involvement of Ras and/or Rho proteins in the induction of the inducible isoform of nitric oxide synthase (NOS II) we used HMG-CoA reductase inhibitors (statins) and Clostridium difficile toxin B (TcdB) as pharmacological tools. Statins indirectly inhibit small G proteins by preventing their essential farnesylation (Ras) and/or geranylgeranylation (Rho). In contrast, TcdB is a glucosyltransferase and inactivates Rho-proteins directly. Human A549/8- and DLD-1 cells as well as murine 3T3 fibroblasts were preincubated for 18 h with statins (1–100 μM) or TcdB (0.01–10 ng ml−1). Then NOS II expression was induced by cytokines. NOS II mRNA was measured after 4–8 h by R…