Effect of insulin on the metabolism of dogs under amytal anesthesia

The effect of insulin on the metabolism of normal fasting dogs has been studied in the respiration calorimeter for four hour periods after its injection. Control experiments were carried out to determine the effect of amytal anesthesia on the heat production of the dog. This anesthetic has no effect on blood sugar 1 and we have found that it has no effect on the CO₂ combining power of the blood.

When sufficient amytal was injected to produce a complete anesthesia (doses from 55 to 65 mg. per kilo, depending on the individual animal), the metabolism remained constant over a six hour period at a level of less than 5 per cent below the basal. On the production of deeper anesthesia by larger doses of this hypnotic, a larger decrease in metabolism occurred (10-25 per cent), but this usually remained constant over a six hour period provided no shivering resulted.

A marked fall in body temperature occurs following the amytal anesthesia which is very rapid at first, and the body temperature usually reaches the minimum value in the second or third hour. With light anesthesia shivering usually resulted when the minimum temperature was reached, by means of which the metabolism was markedly accelerated and the body temperature brought back to normal. With larger doses of amytal, chemical regulation was entirely prevented, although a slow return to normal temperature resulted.

When insulin was injected into a fasting dog under the influence of amytal anesthesia, an increased R. Q. was sometimes obtained during the second hour, while during the third and fourth hours the R. Q. returned to the preliminary level. In other experiments on the same animals no increase in quotient followed the administration of insulin, although the blood sugar fell decidedly below the convulsive level.