In vitro organic nitrate bioactivation to nitric oxide by recombinant aldehyde dehydrogenase 3A1.

Organic nitrates (ORNs) are commonly used anti-ischemic and anti-anginal agents, which serve as an exogenous source of the potent vasodilator nitric oxide (NO). Recently, both mitochondrial aldehyde dehydrogenase-2 (ALDH2) and cytosolic aldehyde dehydrogenase-1a1 (ALDH1A1) have been shown to exhibit the ability to selectively bioactivate various ORNs in vitro. The objective of the present research was to examine the potential role of ALDH3A1, another major cytosolic isoform of ALDH, in the in vitro bioactivation of various ORNs, and to estimate the enzyme kinetic parameters toward ORNs through mechanistic modeling.

Differential metabolism of organic nitrates by aldehyde dehydrogenase 1a1 and 2: substrate selectivity, enzyme inactivation, and active cysteine sites.

Organic nitrate vasodilators (ORN) exert their pharmacologic effects through the metabolic release of nitric oxide (NO). Mitochondrial aldehyde dehydrogenase (ALDH2) is the principal enzyme responsible for NO liberation from nitroglycerin (NTG), but lacks activity towards other ORN. Cytosolic aldehyde dehydrogenase (ALDH1a1) can produce NO from NTG, but its activity towards other ORN is unknown.

Simultaneous bioanalysis of L-arginine, L-citrulline, and dimethylarginines by LC-MS/MS.

Purpose: L-Arginine (ARG) is converted to nitric oxide (NO) and L-citrulline (CIT) by endothelial nitric oxide synthase which is competitively inhibited by asymmetric dimethylarginine (ADMA). We have developed a liquid chromatography-mass spectrometric method for the simultaneous determination of endogenous ARG, labeled ARG (¹⁵N₄-ARG), CIT, ADMA, and its inactive isomer, symmetric dimethylarginine (SDMA) in biological samples.

Methods: Concentrations of unlabeled ARG, ¹⁵N₄-ARG, CIT, ADMA, and SDMA in EA.

Nitroglycerin alters matrix remodeling proteins in THP-1 human macrophages and plasma metalloproteinase activity in rats.

Several studies suggested that long-term nitrate therapy may produce negative outcomes in patient mortality and morbidity. A possible mechanism may involve nitrate-mediated activation of various extracellular matrix (ECM) proteases, particularly matrix metalloproteinase-9 (MMP-9), and adhesion molecules in human macrophages, leading to the destabilization of atherosclerotic plaques. We examined the gene and protein regulating effects on THP-1 human macrophages by repeated exposure to therapeutically relevant concentrations of nitroglycerin (NTG) and possible involvement of nuclear factor (NF)-κB signaling mechanism in mediating some of these observed effects.

Pharmacokinetics of 1,4-butanediol in rats: bioactivation to gamma-hydroxybutyric acid, interaction with ethanol, and oral bioavailability.

1,4-Butanediol (BD), a substance of abuse, is bioactivated to gamma-hydroxybutyrate (GHB), but its fundamental pharmacokinetics (PK) have not been characterized. Because this bioactivation is partly mediated by alcohol dehydrogenase, we hypothesized that there may also be a metabolic interaction between ethanol (ETOH) and BD. We therefore studied, in rats, the plasma PK of GHB, BD and ETOH each at two intravenous (IV) doses, when each substance was given alone, and when GHB or BD was co-administered with ETOH.

Simultaneous determination of nitroglycerin and dinitrate metabolites in metabolism studies using liquid chromatography-mass spectrometry with electrospray ionization.

We have developed a liquid chromatographic-mass spectrometric method for the simultaneous determination of nitroglycerin (NTG) and its active metabolites, glyceryl 1,2-dinitrate (1,2-GDN) and glyceryl 1,3-dinitrate (1,3-GDN), for metabolism studies in cell cultures. 1,2,4-Butanetriol-1,4-dinitrate was chosen as an internal standard. Using a linear gradient of water/methanol containing 0.

Liquid chromatographic-mass spectrometric determination of endogenous gamma-hydroxybutyrate concentrations in rat brain regions and plasma.

A new liquid chromatographic-mass spectrometric (LC-MS) method for determining trace concentrations of gamma-hydroxybutyric acid (GHB) in biological samples has been developed. This method utilizes solid-phase extraction for separation, deuterated GHB as an internal standard (IS) and multiple reaction monitoring (MRM) in the negative ion mode to detect the parent and product ions (103 and 57 for GHB, and 109 and 61 for D6-GHB, respectively). The assay produces excellent linearity and reproducibility, with a limit of quantification (LOQ) of about 0.

eNOS-dependent vascular interaction between nitric oxide and calcitonin gene-related peptide in mice: gender selectivity and effects on blood aggregation.

The present study was performed to explore a possible vascular interplay between nitric oxide (NO) and calcitonin gene-related peptide (CGRP). We examined factors affecting CGRP release by the NO donor, nitroglycerin (NTG) and the potential involvement of endothelial NO synthase (eNOS) using eNOS knockout (-/-) vs. wild-type (+/+) mice.