Glycogenolysis in Aliquots of Glycogen Bodies of the Chick

Abstract

PREVIOUS attempts to change the glycogen concentration in the glycogen body of birds failed^1–4 except for a few cases in which it was slightly increased^5,6. In the experiments recorded here the effect of tissue homogenates on the polysaccharide of the glycogen body of the chick was examined. Glycogen bodies of chicks 1–4 weeks old were isolated, weighed on a Roller Smith torsion balance and homogenized in glass tissue-grinders. Ringer's solution, or isotonic sodium chloride buffered with 0.01 M phosphate to pH 7.4, was added to the homogenate in the proportion of 1 ml. per mg of tissue. Twenty-four aliquots of 1 ml. were then prepared from the homogenate and were divided into 4 groups of 6 each. Ringer's solution (0.2 ml.) was added to the aliquots of one group and 0.2 ml. of tissue homogenate (containing 20 mg of chick skeletal muscle, liver or brain) to the others. To the samples of the first group, in 2 series of experiments, ATP, DPN⁺ and glucose-6-phosphate (1 mg. each) were added. Two aliquots of each group were extracted⁷ for glycogen immediately, two after 4 h and 2 after 24 h of incubation at room temperature (70° F.). Glycogen was assayed colorimetrically by the anthrone method⁸.