To the Editor.—
A recent publication by Halprin et al1 aided the understanding of epidermal glycogen metabolism. Space limitations preclude the rigorous discussion of rationale that this report deserves, but several points require clarification.Adenosine-3′, 5′-cyclic monophosphoric acid (cyclic AMP) and theophylline were mentioned in the "Material and Methods," section, but there is no further reference to their use. The source of a α-glucosidase was not reported; as we noted recently,2 purified enzyme is available from Boehringer Mannheim Corp (No. 15043 EAAU). In our hands, there is no need to augment this preparation with α-amylase to obtain quantitative glycogen hydrolysis. The reference to Huijing3 for glycogen assay details applies only to the glucosidase incubation step, since he detected glucose with glucose oxidase, and Halprin et al employed a fluorometric hexokinase-based assay.The comment that 0.2-mm keratome slices of normal and psoriatic skin contained about 85% epidermis is
Johnson JA, Fusaro RM. Glycogen Turnover in Epidermis. Arch Dermatol. 1973;108(5):724–725. doi:10.1001/archderm.1973.01620260068029
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