Effect of Insulin on Blood Sugar of Rabbits During Infection

Abstract

It is generally believed that the effect of insulin is diminished during infection in diabetes patients, and that temporarily more must be given to maintain a normal blood sugar level. To obtain information on the subject the following experiments were performed:

Healthy rabbits were injected intravenously with 0.5 unit of insulin per kg. of body weight. The blood sugar was determined by the Folin-Wu-Benedict method before insulin injection and thereafter at 15 to 30 minute intervals for 3 1/2 hours. After at least 2 curves were obtained on successive days, the rabbits were inoculated intracutaneously with 0.1 cc. of a 1-400 dilution of a culture of Type I pneumococci. Usually on the next day, when the temperature and local reaction indicated the development of infection, the insulin injection and blood sugar determinations were repeated. Tests were made daily, usually for 2 or 3 days until the animal died or recovered.

Results. In general, similar results were obtained in all 6 animals. A typical experiment is illustrated in the text-figure. It appears that insulin administered during infection takes a little longer to produce its maximum effect, but the effect is more pronounced and lasts considerably longer. It also appears that the effect on reducing the blood sugar is in proportion to the gravity of the infection. In one animal, after insulin injection on the second day of infection the blood sugar dropped progressively to 78 mg. in 1 1/4 hours when death occurred. In another (temp. 41°C.) the level dropped even more rapidly. Convulsions occurred when the level dropped below 50 mg. and death followed about 30 minutes later with a level of 22 mg.