The effect of serum calcium levels on the rate of epidermal renewal in the rat

Abstract

The growth and differentiation of epidermal cells in vitro show a marked dependence on the calcium concentration of the medium. In this study the effect of experimentally produced hyper‐and hypocalcaemia on the rat epidermis in vivo has been investigated. Hypercalcaemia, induced by injections of calcium chloride, produced a decrease in epidermal labelling index and some epidermal thinning. On the other hand hypocalcaemia, induced by calcitonin, failed to lead to changes in these measurements. The diurnal variation in epidermal labelling index and serum calcium levels was also measured. Whilst the labelling index decreased considerably over the period 09.00 hours to 18.00 hours, no significant changes were observed in serum calcium. These results suggest that while, under certain circumstances in vivo, the epidermal cell shows the same sensitivity to calcium as it does in vitro, calcium is not a major regulator of epidermopoiesis.