The effect of iletin (insulin) on the blood sugar content in adrenalectomized animals

Abstract

The existence of a close relationship between the adrenals, especially the medulla, and the pancreas in the regulation of the carbohydrate metabolism has been assumed by various writers. It seemed therefore of interest to determine whether the action of insulin on rabbits which had survived total adrenalectomy differed from its action on normal rabbits. No difference was made out. The adrenals were removed in two operations. The second adrenal was excised 3 weeks to 8 months before the insulin experiment. Six to eight blood specimens were obtained at intervals during 4 to 6 hours after subcutaneous injection of insulin. The blood sugar followed the course described by Macleod and his collaborators in normal rabbits, falling from initial values of 0.10 to 0.1 1 per cent. to a minimum of 0.039 to 0.048 per cent. (Folin-Wu method). When convulsions occurred, or the animal became comatose without going into convulsions subcutaneous injection of dextrose had the same markedly beneficial effect as in the normal control animals. Usually there was some rise in the rectal temperature (as much as 1.5° C. in a case where the animal became comatose without convulsions, and 2° C. in a case where convulsions occurred and dextrose was injected).

If the internal secretion of the pancreas and the internal secretion of adrenal medulla both take a share in the regulation of the blood sugar content (perhaps, as some have supposed, by exerting actions more or less antagnostic) it might appear not unlikely that each would influence the secretion of the other. We have accordingly made some experiments on the influence of insulin upon the output of epinephrin in the cat, in which animal the blood sugar curve after insulin runs much the same course as in the rabbit, Neither with subcutaneous nor with intravenous injection of insulin was any decided effect produced upon the output.