The Metabolism of Normal and Neoplastic Skin Epithelium: Evidence against the Theory that Aerobic Glycolysis Associated with a Low R.Q. is a Feature of a Disturbed Metabolism Indicative of Tumour Growth

Abstract

Since the normal epithelial cells of the rabbit's skin can be readily transformed into tumour cells by means of the Shope papilloma virus, a biochemical study of the characteristic differences between the two seemed desirable. Experiments were therefore undertaken involving measurements of the oxygen uptake, aerobic and anaerobic glycolysis, and the respiratory quotient of normal skin epithelium and of Shope papilloma growing in the domestic rabbit. Methods The metabolic study of skin epithelium in vitro necessitated certain special methods. 1. A microrespirometer of sufficient sensitivity. The instrument described by Heatley, Berenblum and Chain (1939) was used for these investigations. 2. A suitable adaptation of the instrument for R.Q. determinations. The indirect method of Dickens and Simer (1931) was adapted for use with the microrespirometer mentioned above, a special “cup” (Fig. 1) being used, which allows two pairs of droplets (1–2 and 3–4) to be mixed independently. Test experiments on bacteria and brain tissue showed that the values obtained were sufficiently reliable as far as the inferences drawn in this paper are concerned. 3. A microchemical method for lactic acid estimation. A modified form of Lehmann's enzymatic method (1938) was used, in which the excess of ferricyanide was estimated iodometrically, adapted to the Holter-Linderstrom-Lang technique. Preliminary tests with known amounts of lactic acid (of the order of 3–10 γ), added to skin, showed reasonably good recovery.