Serum Glutathione Reductase Research Articles

Letter: Serum glutathione reductase and cystic fibrosis.

Letter: Serum glutathione reductase and cystic fibrosis.

Clinical significance of serum glutathione reductase in various clinical conditions, especially in liver diseases.

Serum glutathione reductase activity was measured in various conditions including acute hepatitis, chronic hepatitis, liver cirrhosis, malignant neoplastic diseases, and obstructive jaundice. A statistically significant elevation of the enzyme activity was found in all of these clinical conditions above normal value, especially in patients with acute hepatitis, some liver cancer, and malignant biliary obstruction. Comparison with other liver function tests showed the existence of statistically significant correlations of serum glutathione reductase with SGOT, SGPT and alkaline phosphatase in acute hepatitis, and with alkaline phosphatase in cirrhosis. In parenchymatous liver disease, serial determination was found to be important. High values in obstructive jaundice suggest the malignant obstruction.

An optimized semi-automatic rate method for serum glutathione reductase activity and its application to patients with malignant disease.

An improved and optimized method for serum glutathione reductase is described. The reference range for normal subjects is 47-79 IU/1. The method is more sensitive than conventional enzyme tests in the detection of malignant disease. It was not raised more frequently in patients with clinical evidence of metastases than in those clinically free of such metastases, and it did not seem to correlate with prognosis among those patients who failed to survive six months from the time the analysis was first conducted.

Serum Glutathione Reductase and Cystic Fibrosis

Extract: Serum glutathione reductase (NADPH:GSSG oxidoreductase, EC. 1.6.4.2 (GR)) has been examined in cystic fibrosis subjects (CF), obligate CF heterozygotes, and control subjects. Serum protein concentration was similar in the three groups. Regardless of the units used to express activity (milligrams of protein or milliliters of serum) or whether or not samples were dialyzed against water or phosphate buffer, mean serum GR in CF was greater than in control subjects (P ≤ 0.002) in all series over several years. Under the above assay conditions no difference in serum GR between control subjects and carriers was detected. Calculated and assayed values of combined control and CF sera agreed as did expected and observed 50% activity in 1:2 sera dilutions in CF, control subjects, and carriers. Addition of FAD to incubation media did not effect enzyme activity in the three groups. Differences between CF and control subjects persisted after dialysis in membranes permitting passage of molecules of approximately 12,000 mol wt or less. These findings would tend to exclude the effect of extraneous serum factors in explaining the differences between CF and control subjects. The percentage of initial GR activity after four days storage (0-4°) was significantly greater in CF than in control subjects (P < 0.025). The effect of heparin on serum GR was recorded as the percentage of activity after incubation with heparin vs. activity in the standard assay for individual subjects. The effect of incubation with 5 μg/ml heparin on serum GR activity was greater in control subjects than in carriers (P < 0.0005) and CF (P < 0.0005). Mean serum GR activity in CF and carriers was unaffected by heparin, whereas mean activity in control subjects was decreased. In no control was the percentage of initial activity with heparin greater than the mean of CF and carrier groups. Only 3 of 20 CF and 4 of 20 carrier individuals had percentages lower than the control mean. The CF and carrier distributions were clearly different from the control distribution. Serum GR was determined in seven non-CF individuals with chronic obstructive pulmonary disease (COPD). Activity in the COPD was different from CF and no different from control subjects. In none of these controls or COPD was serum GR as great as the CF mean. Serum GR in no CF was as low as the mean of control subjects or COPD. It is concluded that serum GR activity is greater in CF than in control subjects, carriers, and non-CF COPD subjects; that the difference in activity is not attributable to an extraneous serum factor, that the activity difference is not secondary to chronic respiratory disease; that in comparison with control subjects, GR from CF serum behaves differently after storage; and that serum GR from CF and carriers behaves differently from control GR in the presence of heparin.Speculation: Abnormal activity of glutathione reductase may be fundamentally related to the pathogenesis of cystic fibrosis.

Optimierte Bestimmung und Eigenschaften der NADPH-abhängigen Glutathion-Reduktase im Serum. Untersuchungen über die Glutathion-Reduktase im Serum, I. Mitteilung

Reaction conditions were optimized for the determination of serum glutathione reductase, which has not yet been investigated systematically. Imidazole was found to be the most suitable buffer material; the highest glutathione reductase activity in serum was always obtained with imidazole/HCl buffer, which, in contrast to all other tested buffers, also resulted in the maximal enzyme activity without preincubation. In imidazole buffer, the pH-activity curve of serum glutathione reductase shows a broad optimum between pH 6.5 and 6.9. A GSSG concentration of 2 mmol/l and a NADPH concentration of 0.43 mmol/l gave maximal enzyme activity and a linear reaction over 10 min up to 20 U/l test solution. An investigation of serum glutathione reductase activity from 100 clinically healthy probands gave values between 20 and 50 U/l. In the optimized assay system the glutathione reductase in the serum reacts specifically with GSSG and NADPH.

The Oxidation of Glutathione by Serum

Abstract Studies of serum glutathione reductase activity in this laboratory prompted an attempt to demonstrate glutathione oxidase in the serum. The oxidation of reduced glutathione in the sera of patients with various diseases does not differ from normal sera. Preheating the serum and addition of cytochrome c does not effect the oxidizing capacity of the serum. The ability of serum to oxidize reduced glutathione appears to represent autoxidation, not the effect of an oxidizing enzyme.

Serum enzyme activities in patients with polycythemia and myelofibrosis. Glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, lactic dehydrogenase, and glutathione reductase in serum of patients with polycythemia and myelofibrosis.

Serum enzyme activities in patients with polycythemia and myelofibrosis. Glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, lactic dehydrogenase, and glutathione reductase in serum of patients with polycythemia and myelofibrosis.