Effect of oleic and octanoic acids on glucose-induced insulin release in vitro

The isolated perfused rat pancreas was utilized to characterize the effect of 1.5 mM oleic acid and 1.5 mM octanoic acid on insulin release in response to glucose (4.4, 8.3, 11.1, 16.7 and 27.7 mM). Both oleic and octanoic acids potentiated glucose-induced insulin release without modification of the pattern of secretion. At 4.4 mM glucose, the potentiation of insulin release by fatty acids was clearcut for the first phase but not significant with respect to the total amount of insulin released during the stimulation period. Maximal potentiation was observed at 11.1 mM glucose both with oleic and octanoic acids. At all glucose concentrations, octanoic acid was more effective than oleic acid in the potentiation of the insulin secretion.