The presence of a blood-sugar reducing substance in yeast

Abstract

In 1914 one of the present authors reported in collaboration with v. Schoenborn that pigeons kept on a vitamine-free, artificially compounded diet, show complete disappearance of the glycogen in the liver and increased blood sugar. In one particular series of experiments the blood sugar amounted to 0.29 per cent. and no glycogen was found in the liver. In a few pigeons kept on the same diet one dose of vitamine B from yeast was injected intramuscularly with the result that liver was found to contain 0.6 per cent. of glycogen and the blood 0.19 per cent. sugar. This vitamine preparation, which proved to be very potent, was prepared in the following way: an evaporated alcoholic extract of yeast was precipitated with phosphotungstic acid, and the resulting dried precipitate treated with acetone. The insoluble fraction was decomposed with lead acetate and the filtrate freed from adenine by means of picric acid. This observation gains much interest in view of the recent communications of Winter and Smith and also of Collip on the presence of an insulin-like substance in yeast and other starting materials. For some time past we have been working on the same problem again. We have found that crude extracts of yeast and rice-polishings possess a blood-sugar increasing rather than decreasing action. When we took, however, yeast grown in the laboratory on a medium rich in vitamine D, then centrifuged and washed the cells, and after heating to 100° injected them subcutaneously into rabbits, we obtained in a number of instances in 3-4 hours blood-sugar decreases which amounted to 30-40 per cent. of the initial value. We agree with Collip that compared with insulin the action of the yeast substance is slow, but on the other hand it lasts longer which might prove of therapeutic advantage. We have not as yet succeeded in obtaining similar results with Fleischmann's yeast treated in the same way.