AN IN-VITRO ABNORMALITY OF GLUTATHIONE METABOLISM IN ERYTHROCYTES FROM NORMAL NEWBORNS: MECHANISM AND CLINICAL SIGNIFICANCE
Authors: Zinkham William H. 
Published: December 2021

When erythrocytes from a group of 66 normal Negro and white infants, 1 to 84 hours old, were incubated with acetylphenylhydrazine, a marked decrease in concentration of reduced glutathione (GSH) occurred. Concentrations of GSH in whole blood of these infants were the same or higher than those observed in normal adults. The degree of GSH instability was less marked in those infants older than 36 hours.

The addition of alpha-tocopherol or plasma of adults to erythrocytes of infants did not alter the abnormal GSH stability test.

Assays for activity of glucose-6-phosphate dehydrogenase were performed with erythrocytes from a group of 40 normal Negro and white newborns with an age range of 1 to 81 hours. The majority of these infants manifested abnormal GSH stability tests. Activities of the enzyme in 37 of these infants were 219.8 to 406.3 units. In a group of 38 normal adults the activities were 149.9 to 216.5 units/100 ml of erythrocytes. Three Negro male infants with activities of the enzyme less than 43.3 units were observed, and a genetic background for this deficiency of enzyme was demonstrated in the mothers of these babies.

The abnormal GSH stability test in those infants with normal activity of glucose-6-phosphate dehydrogenase in erythrocytes was corrected by the addition of glucose in sufficient quantity to result in final concentrations of 30 to 160 mg/100 ml. Additional glucose had no effect on the results of the GSH stability test performed with bloods from four Negro infants with diminished activity of the enzyme.

Concentrations of glucose in whole blood of infants, incubated aerobically with menadione sodium bisulfite at 37°C for 2 hours, were usually 11 mg/100 ml or less, whereas values in blood of adults ranged between 40 and 50 mg/100 ml. By determining concentrations of GSH and glucose simultaneously in blood of infants and adults after the blood had been exposed to menadione sodium bisulfite, it was found that a marked decrease in the content of GSH in erythrocytes occurred when concentrations of glucose of 10 mg/100 ml were attained. No correlation between concentrations of glucose and GSH was demonstrated when blood from a "reacting" adult was incubated with menadione sodium bisulfite. Also, when blood from a normal newborn was incubated aerobically at 37°C for 4½ hours in the absence of menadione sodium bisulfite, the concentration of GSH remained normal, even though concentrations of sugar were less than 10 mg/100 ml during the last 2 hours of incubation.

It is concluded that the abnormal GSH stability test observed in most newborns can be attributed to an in-vitro deficiency of glucose. In a small percentage of Negro babies, however, this alteration of glutathione metabolism is associated with a genetically determined deficiency of activity of glucose-6-phosphate dehydrogenase.

Whether or not newborns with the nongenetic type of GSH instability are unusually susceptible to the hemolytic effects of certain drugs or chemicals has not been settled. At least two infants with the inherited abnormality of metabolism of erythrocytes, however, have responded with severe hemolytic anemia when exposed to menadione sodium bisulfite and naphthalene.

Even though added glucose corrects the in-vitro instability of GSH in erythrocytes of those infants with normal activity of the enzyme, the role of glucose in the evolution of hemolytic anemias occurring in the newborn period has not been determined.