Changes of serum insulin level in lethally irradiated rats.

The levels of serum immunoreactive insulin and blood glucose were measured at 1, 6, 24, 48 and 72 h after the exposure to irradiation (387 mC kg-1 (1500 R) x-rays in male Wistar rats weighing about 200 g and fasted overnight before the irradiation. At 6 h a significant decrease of serum insulin was found which was parallel in both irradiated animals and sham-irradiated controls. This was presumably due to the handling during the irradiation procedure. At later time intervals, the level of insulin in irradiated animals appeared to be relatively stable, while that in controls was significantly increased at 24 h and later showed a steep decline resulting in a significantly decreased level at 72 h. The level of blood glucose was significantly increased in irradiated animals at 6, 24 and 48 h, the average increase at 72 h being about 300 per cent of the level in controls.