Estimation and Distribution of Ascorbic Acid (Vitamin C) and Glutathione in Animal Tissues

Abstract

MOST of the recorded measurements of the reduced glutathione content of tissues have been made by Tunnicliffe's method of titration with iodine on the assumption that the trichloracetic extracts of tissue contain little else but glutathione capable of reducing iodine in acid solution. A method depending upon a different principle was introduced by Mason, who found that the reduced glutathione content of liver, kidney and yeast extracts determined by titration against iodine is 120–200 per cent of the true value. His method has however been neglected, and the iodine method has been used almost exclusively. Recently, Bierich has evolved a third method for the estimation of reduced glutathione and has also obtained values much lower than those obtained by iodine titration. Ever since the discovery of ascorbic acid, it has been evident (as is mentioned by these workers) that where ascorbic acid occurs in the tissues, it will be estimated as glutathione in the iodine titration; but it has been assumed without any evidence that ascorbic acid occurs only in traces except in the suprarenal cortex.