Adenosine 5'-monophosphate Levels Research Articles

Online Cleanup of Accelerated Solvent Extractions for Determination of Adenosine 5′-Triphosphate (ATP), Adenosine 5′-Diphosphate (ADP), and Adenosine 5′-Monophosphate (AMP) in Royal Jelly Using High-Performance Liquid Chromatography

Determination of the levels of adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), and adenosine 5'-monophosphate (AMP) in royal jelly is important for the study of its pharmacological activities, health benefits, and adenosine phosphate degradation. In this study was developed a novel method to determine ATP, ADP, and AMP levels in royal jelly using accelerated solvent extraction (ASE) followed by online cleanup and high-performance liquid chromatography (HPLC) with diode array detection (DAD). The optimum extraction conditions were obtained using an 11 mL ASE cell, ethanol/water (5:5 v/v) as the extraction solvent, 1500 psi, 80 degrees C, a 5 min static time, and a 60% flush volume. Optimum separation of the three compounds was achieved in <25 min using a Waters XBridge Shield RP18 column with 0.05 mol L(-1) NH(4)H(2)PO(4) (pH 5.70) and acetonitrile as the mobile phase. Detection was performed at 257 nm. The method was sensitive (LOD <or= 0.32 mg L(-1)), repeatable (RSD <or= 4.5%), accurate (recovery rates of 87.6-94.2% with RSD <or= 5.4), and precise (intraday RSD <or= 8.5%, interday RSD <or= 3.4%). The ASE extraction procedures developed here were compared with the classical adenosine phosphate extraction procedures (perchloric acid). The results indicate that the two techniques are similar in terms of recovery and reproducibility, but when other factors such as extraction time, environmental protection, and worker's health are considered, ASE is preferable to the classical extraction method. With this ASE-HPLC method, a minisurvey of ATP, ADP, and AMP levels in 15 samples of royal jelly of different origins was performed. Sample results indicated that the AMP concentration was 24.2-2214.4 mg kg(-1), whereas ATP and ADP were not detectable or present only at low levels.

Phenol-Containing Saline Solution as a Diluent for Adenosine 5′-Monophosphate in Bronchial Challenge Testing

To investigate the effect of dissolving adenosine 5'-monophosphate (AMP) with phenol-containing saline solution on the stability and the bronchoconstrictive properties of this indirect agonist. Eleven subjects with asthma well controlled with short-acting inhaled beta2-agonists as required or with inhaled corticosteroids were studied. Bronchial challenge tests with AMP dissolved with either normal saline solution or saline solution containing 0.4% phenol were performed on separate days. Furthermore, to assess the potential influence of the phenol-containing saline solution on the stability of the bronchoconstrictor agent, AMP solutions in concentrations of 40 microg/mL and 400 microg/mL were prepared in saline solution and phenol-containing saline solution and, after 30 min, the AMP levels were determined by high-performance liquid chromatography (HPLC) assay. The geometric mean AMP provocative concentration causing a 20% fall in FEV1 (PC20) was 13.49 mg/mL (95% confidence interval [CI], 6.76 to 26.91) for the saline solution method, and AMP PC20 for the saline solution with phenol method was 8.91 mg/mL (95% CI, 3.39 to 23.44) [p = 0.18]. No significant differences were found between the concentrations of AMP made in saline solution compared to those made in phenol-containing saline solution measured by HPLC. These observations indicate that normal saline solution with or without phenol can be used as the diluent for AMP. However, since a potential risk with AMP of industrial sources is the bacterial contamination, adding a preservative such as phenol to a saline solution diluent might be recommended.

Hepatic mitochondrial energy production in rats with chronic iron overload

Background: Iron overload results in impaired hepatic mitochondrial oxidative metabolism. The current experiments evaluated the effects of iron overload on enzyme activities in the mitochondrial electron transport chain, on hepatic adenine nucleotide levels, and on hepatocellular oxygen consumption. Methods: Hepatic iron overload was produced in rats using dietary carbonyl iron. Hepatic adenine nucleotides were assessed after freeze-clamping, mitochondrial enzyme activities and oxygen consumption were measured in isolated mitochondria, and oxygen consumption in isolated hepatocytes was determined. Results: At a mean hepatic iron concentration of 4630 μg/g, there were no changes in reduced nicotinamide adenine dinucleotide (NADH)-cytochrome c reductase activity (complex I–III), but there was a 35% reduction in succinate-cytochrome c reductase activity (complex II–III), and a 70% decrease in cytochrome c oxidase activity (complex IV). With mild iron loading (2060 μg/g), there was a 28% decrease in hepatic adenosine 5′-triphosphate (ATP) levels with no change in adenosine 5′-diphosphate (ADP) or adenosine 5′-monophosphate (AMP) levels, whereas, at a higher hepatic iron concentration (3170 μg/g), there was a 40% reduction in ATP levels, a 22% decrease in ADP levels, with no change in AMP levels. There was a 48% reduction in oxygen consumption in isolated iron-loaded hepatocytes. Conclusions: Chronic iron overload decreases hepatic mitochondrial cytochrome c oxidase activity, hepatocellular oxygen consumption, and hepatic ATP levels.