Dehydrogenase activity, serum lactic

Amador, E. Dorfman, L. E. and Wacker, W. E. C. Serum lactic dehydrogenase activity. An analytical assessment of current assays. Clin. Chem. (1963), , 391-399. 

Cyprinus carpio 0.5 after 6 days, 300% increase in phosphorylase and 200% increase in glucose-6-phosphatase activities in liver increase in sugar level and serum lactic dehydrogenase activity 18... 

Chronic in vivo hemolysis produces serum lactic dehydrogenase elevations in patients with mitral or atrial valve cardiac prosthesis (J2). In a series of 11 such patients these increases ranged from 1.1 to 1.6 times the upper limit of normal (S29). Blood pH is altered in hemolyzcd specimens because carbonic anhydrase is liberated from the erythrocytes and presumably alters the distribution of H2CO3 and NaHCOs (B2). Hemolysis will effect acid phosphatase activity if the substrate is hydrolyzed by erythrocyte acid phosphatase. Thus, hemolysis would be of concern if phenyl phosphate was the substrate, but would have a negligible effect if )8-glycerophosphate, which is not hydrolyzed by red cell acid phosphatase, was used (Bl). 

Inhibitors of lactic dehydrogenase have been reported in commercial preparations of NAD+ and NADH (B4, M6, S28). The concentration of inhibitory substances varied from lot to lot. In a serum lactic dehydrogenase study with NAD+ from 8 sources, activities were found to vary from 145 to 75 units (B4). Inhibitors of lactic dehydrogenase activity have also been observed in dialyzates in uremic patients (W8) and in human urine (G8). The purity of available substrate can also effect enzyme activity. Schwartz and Bodansky observed that, in 6 batches of fructose 6-phosphate, all weighed to a 0.5 mM concentration, the actual concentration varied from 0.13 mAf to 0.55 mM (S14). 

Clinical Biochemical Determinations of the Serum Serum lactic dehydrogenase (LDH) and glutamic-pyruvic transaminase (GPT) activities were measured on fresh, refrigerated serum within U8 h of sacrificing the animal. Lactic dehydrogenase was measured according to the method of Amador, Dorfman, and Wacker (12). Serum GPT activity was measured according to the method of Wroblewski and LaDue (13). 

Both are abundant in skeletal muscle, myocardium, liver, and erythrocytes, so that hemolysis must be avoided, and in serum they may be assayed spectrophotometrically by their conversion of phosphate-buffered pyruvate to lactate (R6, W16) or oxalacetate to malate (S25) at the expense of added NADH2, when the rate of decrease of optical density at 340 m x thus measmes the serum activities of the respective enzymes. Recently, however, the reverse reaction has been found best for serum lactic dehydrogenase assay (A2a). In conventional spectrophotometric units the normal ranges are 100-600 units per ml for lactic dehydrogenase (W16) and 42-195 xmits per ml for malic dehydrogenase (S25) as before, one conventional spectrophotometric unit per ml = 0.48 pmoles/ minute/liter (W13). 

The effects and the safety of a 5-day regimen of G-CSF (n = 9) or GM-CSF (n = 8) have been compared (10). Most patients complained of flu-Uke symptoms in both groups (six and seven respectively), but rash at the injection site was observed only in four patients treated with GM-CSF. In the G-CSF group, there was a fall in platelet count (below 150 x 10 /1) in five patients, raised serum lactic dehydrogenase activity, and raised uric acid concentrations three patients required transient treatment with allopurinol. 

Enzymes activities are particularly sensitive to the anticoagulant used in collecting the specimen. Heparin inhibits acid phosphatase (W16) and muramidase (Z5). Amylase activity is inhibited by oxalate or citrate (MIO), and lactic dehydrogenase and acid phosphatase lose activity in oxalate (C2). Alkaline phosphatase is stable in oxalate, oxalate-fluoride, or heparin, but 25 mAf citrate inhibits 50% of the activity, and as little as 50 mlf EDTA is completely inhibitory (B19). Leucine aminopeptidase is inhibited by EDTA, as is creatine phosphokinase (F3). Amylase activity has been reported to be only 83% of that in serum when oxalate or citrate-plasma is used (MIO). Heparin plasma appears to have no inhibitory effect. Despite the fact that clotting factor V is not stable in oxalate or EDTA, these are often used as anticoagulants to obtain plasma for prothrombin determinations (Z2, Z4). 

Again, the enzyme lactic dehydrogenase frequently shows elevated serum activity in muscular dystrophy, though it is cleared from serum with remarkable speed in dogs the intravenous injection of purified lactic dehydrogenase immediately raises its serum activity to 10 times the normal value, but after only 1 hour the greater part of it has already been removed from the serum (W18). 

Even in normal individuals, however, only moderately strenuous exercise usually causes modest but distinct elevations of the serum activities of aldolase (B6, C5, F3, R3), both transaminases (B6, C5, F3, P12, S21), lactic (B6, C5, F3, T4) and malic (F3) dehydrogenases, and creatine kinase (Al, B6, F2a, R4) which rapidly return to normal after rest, though GPT seems least affected. More sustained military or athletic training programs cause a similar but more persistent rise in these values, but not in that of SGPT (C13, R5). In particular it has been found that serum aldolase activity in untrained subjects rises immediately after 5-10 minutes of exercise, falls to normal shortly afterwards, then rises again briefly from these normal values to fm-ther maxima at 30 minutes and again at 90 minutes after termination of the exercise (R3). It is of in-... 

Soltan, H. C., and Blanchaer, M. C., Activity of serum aldolase and lactic dehydrogenase in patients affected with Ducherme muscular dystrophy and in their relatives. J. Pediat. 54, 27 (1959). 

The authors also measured the activity of serum glutamic oxalacetic transaminase (SCOT), creatine phosphokinase (CPK), and lactic dehydrogenase (LDH) to determine if there was evidence of myocardial necrosis. They... 

Flora et al, (1982) used other biochemical parameters to study the interaction of selenium and cadmium. The administration of cadmium to rats enhanced the urinary excretion of lactic dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT), and total proteins but decreased the renal activity of GOT and alkaline phosphatase, and renal levels of cadmium, copper, and zinc. Serum GOT and glutamic pyruvic transaminase (GPT) activities and hepatic levels of cadmium and zinc were increased, but the hepatic activities of GOT and GPT were decreased in cadmium-exposed rats. The concomitant administration of selenium reduced most of these cadmium-induced alterations. 

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