The Specific Dynamic Action of Carbohydrates.

Abstract

The speed with which glucose or sucrose may be absorbed and metabolized when it is administered orally would seem to be rapid, judged from observations such as the time necessary for the recovery from insulin hypoglycemia after taking glucose by mouth. No experimental data are on record, however, in which an investigation of this point has been carried out by the method of determining how soon the R. Q. becomes elevated from increased carbohydrate utilization or how soon the specific dynamic action becomes manifest after carbohydrate ingestion in normal animals. In the experiments of Lusk 1 on the specific dynamic actions of the common sugars, carried out on dogs in the respiration calorimeter at Cornell University Medical College, technical difficulties have prevented a determination of the effects of the carbohydrate during the first hour following its administration.

The experiments described below were conducted by making use of the open circuit type of respiration apparatus, which allowed metabolism determinations in the interval immediately following the ingestion of the different carbohydrates. The experiments were carried out on one of us (H. J. D.). The majority of these experiments were done during a period in which the subject was taking a protein-free diet and the others somewhat later during a period of low protein diet. Two basal determinations of 15 minute intervals were carried out each morning before the taking of 75 grams of the carbohydrate under investigation. After the carbohydrate was ingested a series of 11 or 12 determinations of metabolism were performed in the following period of 4 3/4 or 5 3/4 hours. Four of these were carried out during the first hour.

When sucrose or fructose was given orally an increased R. Q. was noted in the first 10 minute period thereafter, while during the second 10 minute interval the R. Q. usually reached the maximum observed during the experiment, often being greater than 1.00.