Changes in sodium-potassium ratio in guinea pig epidermis in n-hexadecane-induced hyperplasia.

A transient epidermal hyperplasia was induced in guinea pig epidermis by a single application of n-hexadecane. The epidermal response was analysed by light microscopy and by energy dispersive X-ray microanalysis (EDX). The epidermal hyperplasia reached a maximum between 96 and 192 h after the application. The hyperplastic response was associated with a depressed sodium-potassium ratio (increased potassium, decreased sodium) in the keratinocytes at 96 h, beginning already at 48 h. At 24 h there were no major differences in elemental content, compared the controls. The result of the present study is consistent with the hypothesis that alterations in the functional state of the epidermal keratinocytes are associated with changes in the sodium-potassium ratio in the cells. The absence of major elemental changes at 24 h indicates that the initiation of the hyperplastic response occurred prior to this time point.