Demonstration of nucleases on mammalian skin surface and in saline extracts of hair.

Abstract

IN the course of experiments on the effects of β-irradiation on the nucleases of guinea pig epidermis we washed thin strips of peeled tissue (25–60µ thick) before homogenization, in an attempt to demonstrate release of enzyme1. Approximately 50 per cent of total deoxyribonuclease (DNase) and 75 per cent of ribonuclease (RNase) activity were thus removed from normal or irradiated epidermis, indicating that considerable amounts of these enzymes may be in the stratum corneum or in the interstitial fluid. This led us to test for the presence of enzymes on the closely clipped skin surface of living animals. For this purpose we adapted the plastic cup technique used by Peiss et al. 2 and Szakall3 for the study of water and ion exchange between a chemically defined medium and the skin. Albino guinea pigs of either sex (500–900 gm.) were fed a vitamin C-enriched diet, anaesthetized with veterinary ‘Nembutal’ and clipped with an electric shaver. Plastic cups were secured to appropriate areas of the animals' flanks by means of ½ in. ‘Trimtex’ rayon elastic, and small alligator clamps or paper clips were used to fasten the elastic (No. S-2 plastic stoppers were supplied by Pioneer Plastics, Box 8066, Arlington Branch, Jacksonville 11, Fla.). Two small needle holes were punched 180° apart and about 6 mm. from the closed end of each cup; 1.5 ml. of 0.9 per cent saline was injected with a No. 22 needle and syringe, and samples were withdrawn for enzyme assay.