Abstract
The incubation of mouse hemidiaphragms in Krebs' buffer containing insulin, but no glucose, results in a stimulation of the formation of glycogen by the tissues; this stimulation is proportional to the concentration of insulin in the range 0 to 100 μU./ml. The glycogen formed by mouse hemidiaphragm during incubation in buffer which contains insulin and (U. C-14) glucose, consists of a labeled and an unlabeled component. The total glycogen, the labeled glycogen and the unlabeled glycogen are all increased by an increase in the concentration of insulin in the incubation medium. Partial fractionation on a column of Sephadex G-200 of glycogen formed by hemidiaphragms incubated in the presence of (U. C-14) glucose with or without insulin, reveals that glucose is incorporated in the smaller glycogen molecules, whereas the larger glycogen molecules are, to a large extent, derived from an unlabeled precursor.