SOME EFFECTS OF INSULIN ON THE BLOOD SUGAR AND INORGANIC PHOSPHORUS LEVELS OF NORMOTHERMIC AND HYPOTHERMIC RATS

Abstract

Blood sugar, inorganic phosphorus, and hematocrit values were measured in hypothermic and normothermic untreated rats and rats injected subcutaneously with insulin. In hypothermic rats the inorganic phosphorus levels were higher than in normothermic animals. The injection of 0.5 units of insulin per kilogram of body weight into fasted normothermic rats caused a significant fall in blood sugar level, but this rose again within 3 hours. The administration of the same amount of insulin to fasted or fed hypothermic rats (colonic temperature of 25 °C) led to a significant fall in blood sugar level, with little tendency for this to rise again at 3 or even at 6 hours. At a body temperature of 20 °C the blood sugar levels continued to fall until very low values were reached. When 0.2 units insulin/kg was injected there was very little hypoglycaemic effect in normothermic rats, but in hypothermic rats (25 °C) a hypoglycaemic effect similar to that obtained with 0.5 units was observed for the first 3 hours, but a significant return toward the initial level was evident by 6 hours. The blood inorganic phosphorus changes after the injection of insulin were not very dramatic and not greatly different in normothermic and hypothermic rats.