Dynamics of insulin release by perfused edible dormouse (Glis glis) pancreas. Seasonal variations.

In order to characterize seasonal variations of beta cell function in the edible dormouse (Glis glis), the dynamics of insulin release were examined during perfusion of the isolated pancreas. The B cells exhibited biphasic insulin secretion; however, the dynamic response differed from that of the rat in that there was a steady-state second release phase. Glucose-induced insulin release changed according to the seasons. With 16.8 mmol/l glucose, the average insulin release of the late phase was 30.8 +/- 12.6 ng/min in winter, 7.4 +/- 3.2 ng/min in spring, 13.1 +/- 3 ng/min in summer and 23.3 +/- 4.4 ng/min in autumn. The glucose-induced insulin release, expressed as percent of the insulin content of the pancreas, varied according to the season: it represented 2.23 +/- 0.31% in winter, 1.28 +/- 0.10% in spring, 1.56 +/- 0.15 in summer and 2.6 +/- 0.11 in autumn. It is suggested that in spring and summer, the edible dormouse B cell secretion mechanism is less sensitive to glucose than in the other seasons.