The effects of hypothermia and insulin on the distribution of glucose in some tissues of the rat

Abstract

In fasted hypothermic rats (25 °C), after a glucose load of 1 g/kg body weight, in either the presence or absence of injected insulin (0.5 units/kg), the rate of disappearance of glucose from the blood was decreased as compared with that of normothermic rats (37 °C). Hypothermia did not change the total water content of diaphragm, rectus abdominis muscle, heart, or liver of these rats, nor did it change the sodium space of these tissues. Insulin-injected hypothermic rats did show an increase in the sodium space of the diaphragm. The glucose space of the muscle tissues was not changed by hypothermia, but was greatly increased by insulin in both hypothermic and normothermic rats. The glucose space of the liver was increased by insulin in normothermic rats, but in hypothermic rats an increase was found only when larger quantitites of insulin were injected. Intracellular glucose could not be detected in the diaphragm, rectus abdominis muscle, or heart of either normothermic or hypothermic rats in the absence of injected insulin, but was present in the liver of both. The injection of insulin caused intracellular glucose to accumulate in the diaphragm and heart of both normothermic and hypothermic rats. The level was increased by hypothermia only in the heart, suggesting that in this tissue the intracellular metabolism of glucose was decreased.