Sect. V, 1922 [35] Trans. R.S.C. 



V. The Effect Produced on the Respiratory Quotient hy Injections 



of Insulin 



By F. G. Banting, M.B., C. H. Best, M.A., J. B. Collip, Ph. D., 

 J. Hepburn, M.B., and J. J. R. Macleod, M.B., Ch.B., F.R.S.C. 



(Read May Meeting, 1922) 



It is generally recognized that the most satisfactory evidence of 

 the utilization of carbohydrate in the animal body is afïorded by 

 the behaviour of the respiratory quotient, i.e., the ratio between the 

 volume of CO2 expired and of O2 absorbed. In the normal animal 

 this quotient approaches unity in proportion as carbohydrates replace 

 fats and proteins in the total metabolism; thus, when sugar is given 

 to the animals that are starving or living on a fat and protein diet the 

 quotient promptly rises. In the completely diabetic animal on the 

 other hand, whether this condition be brought about by removal of 

 the pancreas, by administration of phloridzin or by disease, the 

 quotient remains at the level of about 0.7 (which is characteristic of 

 the metabolism of a mixture of fat and protein) even when large 

 amounts of carbohydrate are ingested. 



At an early stage in our work on the influence of insulin on 

 diabetes it became necessary to observe this quotient. This has 

 been done on a case of severe diabetes in man and on several depan- 

 created dogs. The patient (aet. 29) (Dr. G.) has been suffering from 

 diabetes for six years. During the past few months his diet has 

 contained approximately 10 gms. carbohydrate with total calories of 

 1200. The total daily excretion of sugar has been 15-30 gms., the 

 blood sugar between 0.28 and 0.33 per cent, and acetone bodies 

 always present On February 17th, 1922, while on the above diet, 

 the R.Q. was found to be 0.74 and it remained unchanged in several 

 observations made during the succeeding two hours. Insulin (4 c.c.) 

 was then injected subcutaneously and 20 gm. cane sugar was taken 

 by mouth with the result that the quotient rose to 0. 90 in two hours. 

 In a second observation of the same type, but in which only 2 c.c. of 

 insulin was injected, the quotient rose to 0.82 in about three hours. 

 Results of a similar character were obtained by Dr. W. R. Campbell 

 on two other diabetic patients in the medical clinic of the University. 



The observations on depancreated dogs were carried out by 

 placing a closely fitting mask over the head and connecting it through 

 two-way valves and wide-bore tubing with a spirometer. There 



