Insulin secretion in the hibernating edible dormouse (Glis glis): in vivo and in vitro studies.

Abstract 1. 1. Plasma glucose and insulin have been studied during lethargy and spontaneous arousal of hibernating edible dormouse. During lethargy blood glucose was low while plasma insulin remained at the same level as in other seasons. 2. 2. Plasma glucose and insulin did not fluctuate along the phase of lethargy. During spontaneous arousal plasma insulin rose strongly from the 17°C stage, reaching the higher values at 26°C while blood glucose was only 85 mg/100 ml, then decreased at 37°C. 3. 3. The effect of glucose and temperature on insulin secretion was studied using perfused pancreas preparation from hibernating edible dormice. 4. 4. During the rewarming of the edible dormouse pancreas the insulin release did not occur in response to the absolute extracellular glucose level but occurred in response to a B cell membrane phenomenon which was dependent on the changing rate of glucose level. 5. 5. The effect of glucose and temperature on insulin secretion from perfused pancreas was compared between edible dormouse and homeotherm permanent, the rat. 6. 6. The B cell response to glucose of the dormouse pancreas increased up to 15°C whereas that of the rat only from 25°C. 7. 7. The dormouse insulin secretion reached a peak value at the 30°C of temperature, whereas that of the rat progressively increased until 37°C. 8. 8. These results showed that some biochemical adjustment or process of acclimatization took place in the B cells of the hibernators.