A Note on the Estimation of Adrenaline

Abstract

DURING the progress of other work in this laboratory it was necessary to carry out quantitative estimations of the adrenaline present in the small adrenal glands of the rat and pigeon.The well-known colorimetric method of Folin, Cannon and Denis [1913], described for estimations on glands of about 2 g. in weight, seemed the most suitable for this purpose.On adapting this method to the small glands of about 0 03 g. weight that were being used, results were obtained that showed considerably wider varia- tion than was anticipated.At the same time it was noticed that, under the conditions of our adaptation, the rate of colour change of the adrenaline solu- tion differed from that of the uric acid standard solution.Accordingly it was decided to investigate the effect of such variable factors as temperature on the rate of colour production of solutions of adrenaline, using the glasses of a Lovibond tintometer as a standard against which to match the blue colour.The possibility of loss of adrenaline due to oxidation in the method of extraction employed by Folin, Cannon and Denis was also examined and found to be small but definite.This loss takes place after the addition of sodium acetate to the hot hydrochloric acid extract and was avoided by using cold trichloroacetic acid as the extracting agent.This acid proved satisfactory in every way and gave a clear protein-free filtrate.