Glyceraldehydephosphate Dehydrogenase and Glucose-6-Phosphate Dehydrogenase Activities in Psoriasis and Neurodermatitis and the Effect of Dithranol

The subcorneal and basal parts of the germinal epithelium were microdissected from freeze-dried sections originating within or just outside guttate psoriatic and neurodermite lesions. The activity of glyceradehydephosphate dehydrogenase (EC 1.2.1.12) † and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) † was measured by application of Lowry's microtechniques. The activities of both enzymes displayed a similar pattern with a significant rise in the uninvolved part of the border region of the psoriatic lesion. The increase was greater within the lesion. In the neurodermite lesion an increase was obtained only within the lesion and the activities found were lower than those encountered in psoriasis. A significant correlation was also found between the two enzymes.After treatment with dithranol (1, 8, 9-trihydroxyanthracene) † the activities of the two enzymes in the psoriatic epidermis were depressed in the border region of the blanched non-scaling lesion and within the lesion. The decrease in the activity of glyceraldehydephosphate dehydrogenase was shown to occur only in the basal epidermis. Glucose-6-phosphate dehydrogenase displayed a decreased activity within the treated lesion in both the subcorneal and basal parts of the epidermis. After treatment the correlation between the activities of the two enzymes could no longer be discerned