DIRECT EFFECT OF CORTICOSTERONE UPON INSULIN-SECRETION STUDIED BY 3 DIFFERENT TECHNIQUES

The immediate effect of corticosterone upon insulin secretion rates estimated by 3 different techniques (perfusion of isolated rat pancreas and perifusion or incubation of isolated islets of Langerhans) was studied for 1 hour. 3 corticosterone concentrations were used: 0.02, 0.2 or 20 mg/l. With 4.2 mmol/l glucose, corticosterone did not affect insulin secretion, whereas, with a stimulating glucose concentration (16.7 mmol/l, insulin secretion was inhibited by the 3 corticosterone concentrations tested during incubation experiments, and by only the 2 physiological ones (0.02 and 0.2 mg/l) during islets perifusion and pancreas perfusion experiments. Moreover the inhibitory effect appeared more rapid with perifused islets than perfused pancreas, where only the second insulin secretory phase was disturbed.