The influence of iletin (insulin) on morphine hyperglycemia

Abstract

It has been shown by Macleod and his collaborators that insulin prevents the development of the hyperglycemia caused by etherization, asphyxia, carbon monoxide and piqÛre, or counteracts it if already present. We have demonstrated that while these forms of experimental hyperglycemia are not essentially related to the adrenals, since they can be well elicited in the absence of those glands, this is not the case with the hyperglycemia produced by morphine in the development of which the adrenals seem to intervene in some way. We have therefore tested the influence of insulin upon morphine hyperglycemia in rabbits and cats. Whether morphine was given before, after, or at the same time as insulin, the characteristic effect of insulin upon the blood sugar was always observed. Thus, in a rabbit to which morhpine was administered 1 hour before insulin the blood sugar, which was 0.083 per cent. at the beginning of the experiment and 0.093 an hour after morphine, was 0.047 per cent. an hour after insulin had been injected. The morphine hyperglycemia had not had time to develop before insulin was given, nor did it develop in the 6 hours over which blood samples were collected. In another rabbit morphine was given an hour after insulin when the blood sugar had already fallen from 0.115 to 0.068 per cent. It went on falling to 0.052 per cent, and never even regained the initial value.

In a normal cat morphine and insulin were administered at the same time. A marked hyporglycemia developed, the blood sugar sinking from 0.13 per cent. to 0.033 per cent. A similar experiment was performed on a cat whose right adrenal had been excised and the medulla of the left destroyed by a drill, the left gland being then denervated, 19 days before the experiment.