Synthesis of Glycogen Fractions by Heart Homogenates.

Abstract

Homogenates of rat heart were incubated in Warburg flasks at 37[degree]C to measure the synthesis, if any, of the TCA (trichloracetic acid) soluble and the TCA insoluble glycogen. There was no synthesis of either fraction in Krebs Phosphate Ringer''s, or in 5.4% glucose in an atmosphere of 3% O2. In a medium of 5.4% glucose and an atmosphere of 100% O2, after a 22.5 minutes period of glycolysis, synthesis of TCA soluble glycogen began at a rate of 2.594 mg of glycogen/100 g of tissue/minutes. Fifty minutes later synthesis of TCA insoluble glycogen began at 1/3 the rate of TCA soluble glycogen synthesis. Dog heart, in a 5.4% glucose 100% O2 medium, did not exhibit synthesis of either fraction.