The effect of glutathione on the determination of blood-sugar

Abstract

IN an earlier paper [Herbert and Groen, 1929] it was shown that the discrepancies between the results of blood-sugar methods were due to non-glucose reducing substances present mainly in corpuscles. It appeared that ferric hydroxide filtrates and zinc hydroxide filtrates contained little or none of the non-glucose material, and that therefore the original MacLean method and the original Hagedorn-Jensen method gave figures close to the true sugar value. The non-sugar material was shown to be present in tungstic acid filtrates, and to have a marked effect on all the analytical methods applied to tungstic acid filtrates except that of Benedict [1928]; the Hagedorn-Jensen method, applied to tungstic acid filtrates, was affected most of all. It was suggested that the principal non-glucose substance responsible was glutathione.In the present investigation the effect of pure reduced glutathione on bloodsugar methods has been studied. The work falls into two sections; (1) a study of the effect of glutathione on the analytical methods, when no treatment corresponding to protein precipitation is used, and (2) a study of the behaviour of glutathione in various methods of protein precipitation, using mixtures of plasma and glutathione.Two different samples of glutathione were employed, both of which were received from Sir Frederick Hopkins's laboratories. The first, received in December 1928, was a deliquescent substance, the solutions of which had a smell resembling that of mint. The second sample was received in July 1929, and consisted of the pure tripeptide of glycine, glutamic acid, and cysteine, prepared by Hopkins's new method [1929].The following blood-sugar methods have been used.(1) The Folin-Wu method [1920].(2) The Shaffer-Hartmann method as modified by Somogyi [1926].(3) The Hagedorn-Jensen method [1923].(4) The Benedict method [1928].

Determination of conjugated glucuronic acid by combining enzymatic hydrolysis with lucigenin chemiluminescence

“…The Somogyi-Nelson sample pretreatment (23,24) involved removal of several of the possible interferents by cationic protein precipitation from the addition of Ba(OH)2 and ZnS04. Although most of the interferences were removed from simulated biological samples by this technique, it was found to be unsatisfactory since most of the free glucuronic acid and a small portion of the glucuronides present were also removed with the precipitate.…”

“…This technique was then tested with eight urine samples from healthy adults (five male and three female) between 24 and 35 years of age. These samples were collected from the first morning urination of each of the eight subjects, and were analyzed within 12 h of collection.…”

“…New QC materials have also been reported, but none has yet found wide acceptance. These new materials include organic dyes (24) and the transition-metal complex, [Ru-(bpy)s]2+ (bpy, 2,2'-bipyridine) (25), in solid polymeric supports. These systems in solid supports are easier to handle than traditional solution QC's because of their insensitivity to orientation and absence of spillage or evaporation problems.…”