Cold tolerance in rats following administration of streptozotocin, glucose, insulin and glucose plus insulin
Fall in rectal temperature (Tre) and survival time was determined on exposure to-20°C in adult normoglycemic and diabetic (streptozotocin treated) rats and 1 h following glucose feeding or insulin administration or both and on exposure to-10°C in young rats with and without glucose feeding. The susceptibility to frostbite was determined by exposure of the limbs to freezing mixture of-19°C or-23°C. The rate of fall of Tre was less and the survival time more in glucose and insulin plus glucose treated animals. On the other hand, the rate of fall of Tre was more and the survival time less, in dia betic and insulin-treated animals. The rectal temperature at which the animal died was the same in the control and the treated animals. The susceptibility to frost bite was more in insulin treated and diabetic animals and less in glucose-fed animals. Exposure to cold during the second h after glucose or glucose plus insulin injection did not alter the blood glucose from that obtained at room temperature. In insulin-treated animals the rate of rise of blood glucose during the second h was much higher at low temperature than at room temperature. The rise in blood glucose in diabetic animals was much higher than in normoglycemic animals exposed to cold.