The effects of morin and methotrexate on pentose phosphate pathway enzymes and GR/GST/TrxR enzyme activities: An in vivo and in silico study.

In this study, the mechanisms by which the enzymes glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR), glutathione-S-transferase (GST), and thioredoxin reductase (TrxR) are inhibited by methotrexate (MTX) were investigated, as well as whether the antioxidant morin can mitigate or prevent these adverse effects in vivo and in silico. For 10 days, rats received oral doses of morin (50 and 100 mg/kg body weight). On the fifth day, a single intraperitoneal injection of MTX (20 mg/kg body weight) was administered to generate toxicity. Decreased activities of G6PD, 6PGD, GR, GST, and TrxR were associated with MTX-related toxicity while morin treatment increased the activity of the enzymes. The docking analysis indicated that H-bonds, pi-pi stacking, and pi-cation interactions were the dominant interactions in these enzyme-binding pockets. Furthermore, the docked poses of morin and MTX against GST were subjected to molecular dynamic simulations for 200 ns, to assess the stability of both complexes and also to predict key amino acid residues in the binding pockets throughout the simulation. The results of this study suggest that morin may be a viable means of alleviating the enzyme activities of important regulatory enzymes against MTX-induced toxicity.

In Vivo and in Vitro Regulatory Effect of Silibinin on Some Metabolic Enzyme Activities against Cobalt Induced Toxicity in Rats: A Biochemical Approach.

The study aimed to examine the in vivo inhibition effect of cobalt ion and silibinin on metabolic enzymes such as glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR), and glutathione S-transferase (GST) and their in vitro inhibition effect on 6PGD. Twenty-four Wistar Albino rats weighing approximately 250-300 g were used in the study. The rats were divided into 4 groups as group 1 (control): isotonic serum (0.5 mL i.p), group 2 (cobalt): (150 mg kg/day cobalt), group 3 (silibinin): (100 mg/kg/day silibinin), group 4 (cobalt + silibinin). As a result of the in vivo applications, a statistically significant decrease was observed in the activities of G6PD (p < 0.05), 6PGD (p < 0.05), GR (p < 0.05), and GST (p < 0.05) enzymes in the groups that were administered cobalt compared to the control group. It was also found that the activities of G6PD (p < 0.05), 6PGD (p > 0.05), GR (p > 0.05), and GST (p > 0.05) enzymes increased in groups that were administered cobalt + silibinin compared to the group that was administered cobalt. As for in vitro applications, it was found that different Co2+ ions inhibited 6PGD enzyme which was obtained as a result of purification with IC50 = 346.6 µM value, while silibinin increased 6PGD enzyme activity within the concentration range of 100-750 µM by 40%. As a result, it was found that cobalt ions had an inhibition effect on G6PD, GR, and GST enzymes, which are vitally important for living metabolism, in vitro and in vivo and inhibited 6PGD enzyme activity in vitro, and silibinin increased these enzyme activities in vivo and 6PGD enzyme activity both in vivo and in vitro and decreased the inhibition effect.

Effects of Arbutin on Potassium Bromate-Induced Erythrocyte Toxicity in Rats: Biochemical Evaluation of Some Metabolic Enzyme Activities In Vivo and In Vitro.

In the present study, the inhibitory effect of potassium bromate on the pentose phosphate pathway and intracellular antioxidant systems enzymes (glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR), glutathione S-transferase (GST), and thioredoxin reductase (TrxR)) and the role of arbutin in ameliorating this inhibition were investigated. In the in vivo phase of the study, Wistar Albino rats (28 male adults) were randomly divided into four groups. Control (n = 7): isotonic serum (0.5 mL, i.p), potassium bromate group (n = 7): potassium bromate (100 mg/kg), arbutin group (n = 7): arbutin (i.p.) (50 mg/kg/day), potassium bromate + arbutin, and Group (n = 7): potassium bromate (100 mg/kg) + arbutin (50 mg/kg/day) (i.p). The results of in vivo study showed that the activities of G6PD, 6PGD, GR, and TrxR enzymes were strongly inhibited in potassium bromate groups (p < 0.05). It was determined that GST enzyme activity decreased in the potassium bromate group, but this decrease was not statistically significant compared to the control group (p ⩾ 0.05). A statistically significant increase was found in G6PD, 6PGD, GST, and TrxR enzyme activities in the arbutin group compared to the control group (p < 0.05). The increase in GR enzyme activity was not statistically significant (p ⩾ 0.05). The potassium bromate + arbutin group's enzyme activity increased in comparison to the potassium bromate group and was discovered to be closer to the control group. It was found that potassium bromate inhibited the 6PGD enzyme obtained from rat erythrocyte tissues with IC50 = 346 µM value and Ki = 434.4 µM ± 6.1 value, and the inhibition was noncompetitive.

The Effects of Sodium Tetraborate against Lead Toxicity in Rats: The Behavior of Some Metabolic Enzymes.

This study was planned to research the in vivo effects of lead (Pb) ions and sodium tetraborate (Na2B4O7) on G6PD and 6PGD, which are some of the enzymes of the pentose phosphate pathway, which carries vital importance for metabolism, and GR and GST, which are glutathione metabolism enzymes, and the in vitro effects of the same agents on the 6PGD enzyme. According to the in vivo analysis results, in comparison to the control group, the rat liver G6PD (p < 0.05), and 6PGD (p < 0.01) enzyme activities in the Na2B4O7 group were significantly lower. In addition, GR and GST enzyme activities were insignificantly lower in the Na2B4O7 group compared to the control group (p > 0.05). The Pb group had lower G6PD and 6PGD enzyme activity levels and higher GR and GST enzyme activity levels compared to the control group, while these changes did not reach statistical significance (p > 0.05). In the in vitro analyses of the effects of Pb ions on the 6PGD enzyme that was purified out of rat liver with the 2',5'-ADP-Sepharose 4B affinity chromatography method, it was determined that Pb ions (200-1200 µM) increased the rat liver 6PGD enzyme activity levels by 33%. On the other hand Na2B4O7 was not significantly effective on 6PGD activity. These results will also contribute to future studies in understanding the physiopathology of the states triggered by Pb ions and sodium tetraborate (Na2B4O7).

Ameliorative effects of astaxanthin against copper(II) ion-induced alteration of pentose phosphate pathway and antioxidant system enzymes in rats.

Copper (Cu) is one of the toxic elements that cause environmental pollution. As a result of excessive accumulation of copper in the organism, it causes damage in various organs and tissues and hemolysis in erythrocytes. Astaxanthin (ATX) is a pigment belonging to the xanthophyll family, which is an oxygenated derivative of carotenoids. Thanks to its powerful antioxidant properties, ATX has an extraordinary potential to protect the organism against various diseases, especially cancer. The main objective of this study was to investigate the toxic effect of copper ions on the glucose 6-phosphate dehydrogenase (G6PD), 6-phospho-gluconate dehydrogenase (6PGD), glutathione reductase (GR), glutathione S-transferase (GST), and thioredoxin reductase (TrxR) enzymes and the role of astaxanthin in reducing this effect. In in vivo study, Wistar Albino male rats (n=28) were randomly divided into 4 groups: the control group, copper (Cu2+) group, astaxanthin (ATX) group, and copper + astaxanthin (Cu2++ATX) group. The results show that G6PD enzyme activity in Cu2+ group was strongly inhibited (p ˂ 0.05), while in other groups, there were no significant effects compared to the control group (p ⩾ 0.05). 6PGD enzyme activity was significantly reduced in Cu2+ group compared to that in the control group (p ˂ 0.05), and GR enzyme activity was lower in Cu2+ group compared to that in the control group (p ˂ 0.05). Similarly, when GST enzyme activity was evaluated, a strong decrease was observed in the Cu2+ group compared to that in the control group (p ˂ 0.05), while the enzyme activity in the Cu2++ATX group approached the control group (p ⩾ 0.05). When TrxR enzyme activity level was examined, a statistically significant decrease was observed in the Cu2+ and Cu2++ATX groups (p ˂ 0.05), and the enzyme activity in the ATX group was found to be close to that in the control group. When in vitro results were evaluated, it was observed that copper ions inhibited G6PD enzyme purified from rat erythrocyte tissues with IC50=1.90 µM value and Ki = 0.97 µM ± 0.082 value and the inhibition was non-competitive. From the results, it can be concluded that Cu2+ ions have an inhibitory effect on rat erythrocyte pentose phosphate pathway and antioxidant system enzymes both in vivo and in vitro, and astaxanthin reduces this effect.

Antibiotics as Inhibitor of Glutathione S-transferase: Biological Evaluation and Molecular Structure Studies.

BACKGROUND: The glutathione S-transferases (GSTs) are family of enzymes that are notable for their role in phase II detoxification reactions. Antibiotics have been reported to have several adverse effects on the activity of the enzymes in mammals. AIM: The aim of this study was the structural and biochemical characterization of rat erythrocyte GST and understanding the effects of gentamicin, clindamycin, cefazolin, ampicillin and scopolamine butylbromide on the activity of human erythrocyte GST using rat as a model. METHODS: The enzyme was purified by GSH-agarose affinity chromatography. In vitro GST enzyme activity was measured at 25°C using CDNB as a model substrate. IC50 of drugs was measured by activity % vs compound concentration graphs. Lineweaver Burk graphs were drawn to determine the inhibition type and Ki constants for the drugs. The structure of the enzyme was predicted via Protein Homology/analogy Recognition Engine. RESULTS: In this study, GST was purified from rat erythrocyte with a specific activity of 6.3 EU/mg protein, 44 % yield and 115 fold. Gentamicin and clindamycin inhibited the enzymatic activity with IC50 of 1.69 and 6.9 mM and Ki of 1.70 and 2.36 mM, respectively. Ampicillin and scopolamine butylbromide were activators of the enzyme, while the activity of the enzyme was insensitive to cefazolin. The enzyme was further characterized by homology modeling and sequence alignment revealing similarities with human GST. CONCLUSION: Collectively, it could be concluded that gentamicin and clindamycin are the inhibitors of erythrocyte GST.

The effects of chrysin and naringin on cyclophosphamide-induced erythrocyte damage in rats: biochemical evaluation of some enzyme activities in vivo and in vitro.

In recent years, there have been efforts to develop therapeutic agents that target metabolic enzyme systems in addition to existing treatment in possible cancer treatments. Cyclophosphamide (CYP) is an anticancer drug commonly used in various cancer treatments. Chrysin (CH) and naringin (NR) are natural flavonoids that possess many medicinal and pharmacological properties. In the present study, we aimed to investigate the effect of CH and NR against CYP-induced toxicity on some metabolic enzyme activities. For this purpose, 56 male rats were randomly divided into 8 groups in our in vivo study. The rats were pretreated with CH (25 and 50 mg/kg bw) and NR (50 and 100 mg/kg bw) for 7 days before administering a single dose of CYP (200 mg/kg bw) on the seventh day. According to the in vivo results of our study, it was observed that CH and NR regulated abnormal changes in CYP-induced enzyme activities. In addition, our in vitro study, G6PD enzyme was purified from rat erythrocyte using affinity chromatography. The effects of CH, NR, and CYP were investigated on the purified enzyme. It was determined that CH increased the enzyme activity, CYP ineffective on the enzyme activity, whereas NR inhibited the enzyme activity noncompetitively. Graphical abstract.

Deciphering of The Effect of Chemotherapeutic Agents on Human Glutathione S-Transferase Enzyme and MCF-7 Cell Line.

BACKGROUND: Cancer is the disease that causes the most death after cardiovascular diseases all over the world these days. Breast cancer is the most common type of cancer among women and ranks the second among cancer-related deaths after lung cancer. Chemotherapeutics act by killing cancer cells, preventing their spread and slowing their growth. Recent studies focus on the effects of chemotherapeutics on cancer cells and new chemotherapy approaches that targeting enzymes that catalyze important metabolic reactions in the cell. OBJECTIVE: The aim of this study was to investigate the effects of chemotherapeutic agents, Tamoxifen and 5-FU, on MCF-7 cell line and human erythrocyte GST, an important enzyme of intracellular antioxidant metabolism. METHODS: In this study, it was investigated that the effect of chemotherapeutic agents, Tamoxifen and 5-FU, on MCF-7 breast cancer cell line and performed ROS analyzes. In addition, it was purified glutathione S-transferase (GST), one of the important enzymes of intracellular antioxidant mechanism, from human erythrocytes by using ammonium sulfate precipitation and glutathione agarose affinity chromatography, and investigated in vitro effects of chemotherapeutic agents, 5 - FU and Tamoxifen, on the activity of this enzyme for the first time. RESULTS: it was determined that Tamoxifen and 5-FU inhibited cellular viability and 5-FU increased intracellular levels of ROS, whereas Tamoxifen reduced intracellular levels of ROS. In addition, human erythrocyte GST enzyme with 16.2 EU/mg specific activity was purified 265.97-fold with a yield of 35% using ammonium sulfate precipitation and glutathione agarose affinity chromatography. The purity of the enzyme was checked by the SDS-PAGE method. In vitro effects of chemotherapeutics, 5-FU and Tamoxifen, on GST activity purified from human erythrocytes were investigated. The results showed that 5-FU increased the activity of GST in the concentration range of 77 to 1155 µM and that Tamoxifen increased the activity of GST in the concentration range of 0.54 to 2.70 µM. CONCLUSION: In this study, the effects of tamoxifen and 5-FU chemotherapeutic agents on both MCF-7 cell line and human GST enzyme were examined together for the first time. Our study showed that chemotherapeutic agents (5-FU and Tamoxifen) inhibited cellular viability and Tamoxifen reduced intracellular levels of ROS whereas 5-FU increased intracellular levels of ROS. In addition, 5-FU and Tamoxifen were found to increase the activity of GST enzyme purified from the human erythrocyte.

In vitro effects of some antibiotics on glucose-6-phosphate dehydrogenase from rat (Rattus norvegicus) erythrocyte.

Glucose-6-phosphate dehydrogenase (G6PD) plays a key function in various biochemical processes as they produce reducing power of the cell. Thus, metabolic reprogramming of nicotinamide adenine dinucleotide homeostasis is reported to be an important step in cancer progression as well as in combinational therapeutic approaches. In this study, the effects of the antibiotics, furosemide, cefazolin, cefuroxime, gentamicin and clindamycin on rat erythrocyte G6PD enzyme was studied in in vitro conditions. The enzyme was purified by 2', 5'-adenosine diphosphate Sepharose 4B affinity chromatography in a single purification step with 1825 fold and 83.7% yield. The specific activity of the enzyme was 29.2 EU/mg proteins. The inhibition studies of these antibiotics were carried out on the enzyme revealing that gentamicin, clindamycin and furosemide inhibited the activity of the G6PD with an IC50 of 1.75, 34.65 and 0.526 mM, respectively with Ki of 0.7, 39.8 and 0.860 mM, respectively. All inhibition types were analyzed by Lineweaver-Burk diagram showing noncompetitive inhibition for furosemide and gentamicin while clindamycin inhibited the activity competitively. On the other hand, cefazolin and cefuroxime increased the activity of the enzyme.

Protective effect of chrysin on cyclophosphamide-induced hepatotoxicity and nephrotoxicity via the inhibition of oxidative stress, inflammation, and apoptosis.

Cyclophosphamide (CYP) is a chemotherapeutic agent used in the treatment of autoimmune disorders and malignant diseases. However, its usage is restricted due to its severe side effects, especially hepatotoxicity and nephrotoxicity. This study aimed to investigate the protective role of chrysin (CH) against CYP-induced hepatotoxicity and nephrotoxicity in rats. In the present study, 35 male Wistar rats were randomly divided into 5 groups with each group consisting of 7 rats. The rats were pretreated with CH orally in doses of 25- and 50-mg/kg body weight for 7 consecutive days, and CYP (200-mg/kg body weight, i.p.) was administrated on the 7th day 1 h after the last dose of CH. It was found that CH could ameliorate CYP-induced elevations of ALT, ALP, AST, urea, creatinine, MDA, and hepatorenal deterioration, and enhance antioxidant enzymes' activities such as SOD, CAT, and GPx, and GSH's level. Furthermore, CH reversed the changes in levels of inflammatory, apoptotic, and autophagic parameters such as NF-κB, TNF-α, IL-1ß, IL-6, iNOS, COX-2, Bax, Bcl-2, and LC3B in liver and kidney tissues. To conclude, the findings of this study demonstrated that CH has a protective effect against CYP-induced hepatorenal toxicity.

The antidiabetic and anticholinergic effects of chrysin on cyclophosphamide-induced multiple organ toxicity in rats: Pharmacological evaluation of some metabolic enzyme activities.

Chrysin (CH) or 5,7-dihydroxyflavone is a flavonoid present in various plants, bee propolis, and honey. Cyclophosphamide (CYP) is a chemotherapeutic drug, which is extensively used in the treatment of multiple human malignancies. In our study, we aimed to investigate the effects of CYP and CH on some metabolic enzymes including carbonic anhydrase, aldose reductase, paraoxonase-1, α-glycosidase, acetylcholinesterase, and butyrylcholinesterase enzyme activities in the brain, heart, testis, liver, and kidney tissues of rats. Thirty-five adult male Wistar rats were used. The animals were pretreated with CH (25 and 50 mg/kg b.w.) for seven days before administering a single dose of CYP (200 mg/kg b.w.) on the seventh day. In all the tissues, the treatment of CH significantly regulated these enzyme activities in CYP-induced rats. These results showed that CH exhibited an ameliorative effect against CYP-induced brain, heart, liver, testis, and kidney toxicity.

The Effect of Mercury Chloride and Boric Acid on Rat Erythrocyte Enzymes.

The aim of this study was to investigate the effects of mercury chloride and boric acid on rat (Wistar albino) erythrocyte: glucose 6-phosphate dehydrogenase (G6PD), 6-phosphoglucona-te dehydrogenase (6PGD), thioredoxin reductase (TrxR), glutathione reductase (GR) and glutathione S-transferase (GST) enzymes in vivo, and the rat erythrocyte G6PD enzyme in vitro. In the in vivo study, 24 male rats were divated into three different groups: control (C), mercury chloride (M), and mercury chloride + boric acid (M + BA). At the completion of this study, a significant degree of inhibition for both G6PD and GST enzyme activity was observed in the M groups when compared to the C group (p < 0.05), and no significant effect was observed in the 6PGD enzyme. However, there was significantly increased TrxR and GR enzyme activity of both the M and M + BA groups (p < 0.05). In the in vitro study, the G6PD enzyme from rat erythrocytes was purified with 2',5'-ADP Sepharose-4B affinity chromatography, and the effect of both mercury chloride and boric acid on the enzyme activity was investigated. The results showed that boric acid increased the G6PD enzyme activity while the mercury ions that inhibited the enzyme activity (IC50 values of 346 µM and Ki values of 387 µM) were noncompetitive.

The effect of astaxanthin and cadmium on rat erythrocyte G6PD, 6PGD, GR, and TrxR enzymes activities in vivo and on rat erythrocyte 6PGD enzyme activity in vitro.

In this study, the effects of astaxanthin (AST) that belongs to carotenoid family and cadmium (Cd), which is an important heavy metal, on rat erythrocyte G6PD, 6PGD, GR, and TrxR enzyme activities in vivo and on rat erythrocyte 6PGD enzyme activity in vitro were studied. In in vitro studies, 6PGD enzyme was purified from rat erythrocytes with 2',5'-ADP Sepharose4B affinity chromatography. Results showed inhibition of enzyme by Cd at IC50 ; 346.5 µM value and increase of 6PGD enzyme activity by AST. In vivo studies showed an increase in G6PD, 6PGD, and GR enzyme activities (P Ëƒ 0.05) and no chance in TrxR enzyme activity by AST. Cd ion inhibited G6PD, 6PGD, and GR enzyme activities (P Ë‚ 0.05) and also decreased TrxR enzyme activity (P Ëƒ 0.05). AST + Cd group G6PD enzyme activity was statistically low compared with control group (P Ë‚ 0.05). 6PGD and TrxR enzyme activities decreased without statistical significance (P Ëƒ 0.05); however, GR enzyme activity increased statistically significantly (P Ë‚ 0.05).

The synthesis of N-benzoylindoles as inhibitors of rat erythrocyte glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase.

Glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) play an important function in various biochemical processes as they generate reducing power of the cell. Thus, metabolic reprogramming of reduced nicotinamide adenine dinucleotide phosphate (NADPH) homeostasis is reported to be a vital step in cancer progression as well as in combinational therapeutic approaches. In this study, N-benzoylindoles 9a--9d, which form the main framework of many natural indole derivatives such as indomethacin and N-benzoylindoylbarbituric acid, were synthesized through three easy and effective steps as an in vitro inhibitor effect of G6PD and 6PGD. The N-benzoylindoles inhibited the enzymatic activity with IC50 in the range of 3.391505 µM for G6PD and 2.19-990 µM for 6PGD.

Naringin protects against cyclophosphamide-induced hepatotoxicity and nephrotoxicity through modulation of oxidative stress, inflammation, apoptosis, autophagy, and DNA damage.

Cyclophosphamide (CP) is a common chemotherapeutic agent that is effective against a wide variety of tumors. The associated hepatotoxicity and nephrotoxicity, however, limit its therapeutic use. Naringin (NG) is a natural flavanone glycoside that has pharmacological and therapeutic activities, such as anti-inflammation, anti-apoptotic, and antioxidant properties. Therefore, the present study was undertaken to evaluate the protective effect of NG against CP-induced hepatotoxicity and nephrotoxicity in rats. Rats were pre-treated with NG (50 and 100 mg/kg b.w.) for 7 days before administering a single dose of CP (200 mg/kg b.w.) on the seventh day. CP-induced hepatotoxicity and nephrotoxicity were associated with an increase in serum toxicity markers and a decrease in antioxidant enzyme activities. CP also induced inflammatory responses by increasing the levels of tumor necrosis factor-α (TNF-α), nuclear factor kappa B (NF-κB), interleukin-6 (IL-6), and interleukin-1ß (IL-1ß), and activities of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Moreover, it activated the apoptotic and autophagic pathway by increasing cysteine aspartate-specific protease-3 (caspase-3) expression and light chain 3B (LC3B) level and also increased the expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG), which is the marker of oxidative DNA damage. Pre-treatment with NG (50 and 100 mg/kg), however, significantly decreased serum toxicity markers, increased antioxidant enzyme activities, and regulated inflammation, apoptosis, autophagy, and oxidative DNA damage in hepatic and renal tissues. These results indicated that NG was an effective protectant against CP-induced hepatotoxicity and nephrotoxicity.

Purification of glutathione S-transferase enzyme from quail liver tissue and inhibition effects of (3aR,4S,7R,7aS)-2-(4-((E)-3-(aryl)acryloyl)phenyl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione derivatives on the enzyme activity.

The use of quail meat and eggs has made this animal important in recent years, with its low cost and high yields. Glutathione S-transferases (GST, E.C.2.5.1.18) are an important enzyme family, which play a critical role in detoxification system. In our study, GST was purified from quail liver tissue with 47.88-fold purification and 12.33% recovery by glutathione agarose affinity chromatography. The purity of enzyme was checked by SDS-PAGE method and showed a single band. In addition, inhibition effects of (3aR,4S,7R,7aS)-2-(4-((E)-3-(aryl)acryloyl)phenyl)-3a,4,7,7a-tetrahydro-1H-4,7methanoisoindole-1,3(2H)-dion derivatives (1a-g) were investigated on the enzyme activity. The inhibition parameters (IC50 and Ki values) were calculated for these compounds. IC50 values of these derivatives (1a-e) were found as 23.00, 15.75, 115.50, 10.00, and 28.75 µM, respectively. Ki values of these derivatives (1a-e) were calculated in the range of 3.04 ± 0.50 to 131.50 ± 32.50 µM. However, for f and g compounds, the inhibition effects on the enzyme were not found.

Inhibitory effects of oxytocin and oxytocin receptor antagonist atosiban on the activities of carbonic anhydrase and acetylcholinesterase enzymes in the liver and kidney tissues of rats.

The aim of this study was to investigate the effects of oxytocin (OT), atosiban, which is an OT receptor antagonist, and OT-atosiban chemicals injected to rats on the activities of carbonic anhydrase (CA) and acetylcholinesterase (AChE) enzymes in liver and kidney tissues of rats. For this purpose, four different groups, each consisting of six rats (n = 6), were formed (control group, OT administered group, atosiban administered group, and both OT and atosiban administered group). The rats were necropsied 60 min after intraperitoneal injection of chemicals into the rats. Liver tissues of rats were extracted. CA and AChE enzyme activities were measured for each tissue by using hydratase, esterase, and acetylcholiniodide methods. Activity values for each enzyme obtained were statistically calculated.

Evaluation of new Beckman Coulter 25(OH) Vitamin D assay and potential improvement of clinical interpretation.

INTRODUCTION: The aim of this study was to assess the analytical performances of the newly developed Access2 25-hydroxyvitamin D (25(OH)D) total immunoassay on two analysers, DxI800 and Access2 (Beckman Coulter, Brea, CA, USA), and compare these two and a recalibrated Modular E 170 25(OH)D assay (Roche Diagnostics, Penzberg, Germany) with reference liquid chromatography tandem-mass spectrometry (LC-MS/MS) with special emphasis on clinical diagnosis. MATERIALS AND METHODS: Beckman immunoassays were assessed for imprecision, accuracy, limit of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), linearity, interference, and carryover. One hundred and nineteen samples were run on DxI 800, Access2, and E 170, and agreement with the LC-MS/MS method was evaluated. RESULTS: DxI 800 and Access2 assays showed good performances in terms of LoB, LoD, LoQ, linearity, and interference. All immunoassays showed negative biases ranging from - 8.6% (DxI 800) to - 19.2% (Access2). DxI 800 and Access2 systems had proportional biases, and the E170 system had a constant bias with the largest random error. Concordance correlation coefficient values ranged from 0.941 (CI: 0.917-0.958) for DxI800 to 0.854 (CI: 0.811-0.889) for Access2. Kappa (κ) coefficients were found moderate for Dxl (0.709; CI: 0.581-0.837) and E170 (0.771; CI: 0.587-0.844) and fair for Access2 (0.572; CI: 0.428-0.716). CONCLUSIONS: All immunoassays can be used in routine 25(OH)D measurements, still fairly diagnosing patients' status. Recent standardization attempts seem not to contribute too much to clinical diagnosis. A clinical laboratory must at least be aware of its method to avoid misinterpretation of results.

Effect of astaxanthin and aluminum chloride on erythrocyte G6PD and 6PGD enzyme activities in vivo and on erythrocyte G6PD in vitro in rats.

In this study, we investigated the effect of astaxanthin (Ast) and aluminum (Al) on the erythrocyte glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) enzymes activities in vivo and on G6PD enzyme in vitro in rats. For in vitro studies, G6PD enzyme was purified from rat erythrocyte by using 2',5'-ADP-Sepharose 4B affinity gel. The effects of Ast and Al3+ ion were investigated on the purified enzyme. It was determined that Ast increased the enzyme activity, whereas Al3+ inhibited the enzyme activity noncompetitively (IC50 values; 0.679 mM, Ki values 1.32 mM). For in vivo studies, the rats were divided into the groups: control (Cont.), Al, Ast, and Al + Ast. The last three groups were compared with the control group. In Al group, a significant degree of inhibition was observed in the activity of G6PD and 6PGD enzymes when compared with the control group (P < 0.05), whereas there was an increase in the activities of G6PD and 6PGD enzymes in Ast and Al + Ast groups (P < 0.05).

Purification of glucose-6-phosphate dehydrogenase from rat (Rattus norvegicus) erythrocytes and inhibition effects of some metal ions on enzyme activity.

Glucose-6-phosphate dehydrogenase (G6PD) is the first enzyme on which the pentose phosphate pathway was checked. In this study, purification of a G6PD enzyme was carried out by using rat erythrocytes with a specific activity of 13.7 EU/mg and a yield of 67.7 and 155.6-fold by using 2',5'-ADP Sepharose-4B affinity column chromatography. For the purpose of identifying the purity of enzyme and molecular mass of the subunit, a sodium dodecyl sulfate-polyacrylamide gel electrophoresis was carried out. The molecular mass of subunit was calculated 56.5 kDa approximately. Then, an investigation was carried out regarding the inhibitory effects caused by various metal ions (Fe2+ , Pb2+ , Cd2+ , Ag+ , and Zn2+ ) on G6PD enzyme activities, as per Beutler method at 340 nm under in vitro conditions. Lineweaver-Burk diagrams were used for estimation of the IC50 and Ki values for the metals. Ki values for Pb+2 , Cd+2 , Ag+ , and Zn+2 were 113.3, 215.2, 19.4, and 474.7 µM, respectively.