Changes in the Respiratory Quotient Produced by Subcutaneous Injection of Dioxyacetone and Glucose.

Abstract

Evidence on the availability of dioxyacetone and glucose by the animal organism has led to opposing conclusions. Rabinowitch 1 and Mason 2 have found that dioxyacetone is more readily oxidized than glucose. Ringer and Frankel 3 have shown that in diabetic dogs dioxyacetone is synthesized to glucose. Campbell, Fletcher, Hepburn and Markowitz, 4 obtaining similar results, concluded that dioxyacetone presents no advantage to the organism, since it must be converted to glucose, prior to oxidation. In the present experiments the availability of these two substances has been studied after subcutaneous injection.

Fifteen experiments were performed on a trained dog, in which 10 grams of the substance studied, dissolved in 10 cc. of warm water, were injected subcutaneously. Seven experiments were performed using dioxyacetone, seven using glucose, and one employing sucrose. The dog had been trained to lie quietly with a leak-proof mask on its head, the expired air being collected through Sadd valves into a spirometer. Air was collected before injection, a second sample of air was taken in the first 3 or 5 minutes after injection, and the subsequent collections of air were taken in 5 to 10-minute periods thereafter. An interval of 3 minutes between collections was required for the removal of samples of the collected air from the spirometer. These air samples were kept in glass sampling tubes over mercury and analyzed for CO₂ and O₂ by means of the Haldane-Henderson apparatus.

In the first 5 minutes after injection of dioxyacetone, 5 experiments, starting with an average respiratory quotient of 20, yielded a respiratory quotient of .92, while in 15 minutes the respiratory quotient rose to 1.03. The remaining 2 dioxyacetone experiments, starting with a higher respiratory quotient, due to the feeding of sucrose on the night prior to the experiment, showed an average pre-injection value of 1.11.