Abstract
It has been shown previously 1 that insulin produces a marked diminution in the sugar excretion of rabbits completely poisoned with phlorhizin, whereas the nitrogen excretion during an observation time of four hours is not appreciably diminished. It was concluded that insulin does not directly influence the sugar formation from proteins during phlorhizin poisoning. Since a rather large amount of sugar is retained when phlorhizinized rabbits are treated with insulin, it was assumed that part of this sugar is stored as glycogen. This seemed the more probable, since Ringer, 2 in a recent publication, showed that completely phlorhizinized dogs which excrete less sugar during the action of insulin give rise to the excretion of extra sugar when the action of insulin has worn off.
Six experiments were undertaken in which four rabbits and two cats were used. In all animals glycogen synthesis could be demonstrated. The glycogen was determined by Pflüger's method or by the total carbohydrate method. One protocol is given below. The experimental methods have been described elsewhere. 3
Rabbit 3. February 1, 1924, abdominal window established; food withdrawn. February 4, first phlorhizin day. February 5, second phlorhizin day. February 6, day of experiment.
As will be seen from this table a marked glycogen synthesis occurs, which reaches its maximum in six hours, while the D:N ratio falls to 1.91. After the insulin injections have been discontinued the glycogen accumulated in the liver disappears gradually again, giving rise to extra sugar in the urine.
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