Cephalic phase insulin release in healthy humans after taste stimulation?

In humans little is known as to whether taste solutions applied to the tongue elicit cephalic phase insulin release (CPIR). The aim of this study was to re-examine if any effect of different taste solutions on CPIR occurs. Under fasting conditions healthy human subjects sipped, and washed out their mouths with eight taste solutions (sucrose, saccharin, acetic acid, sodium chloride, quinine hydrochloride, distilled water, starch, and sodium glutamate) for 45 s and spat them out again. The taste stimuli were not swallowed; they were applied in a randomized order, each on a separate day. Blood collection for determination of plasma glucose and plasma insulin concentrations was performed 3 min before and 3, 5, 7 and 10 min after taste stimulation. Ratings of quality, intensity and hedonic characteristics were also obtained. A significant increase of plasma insulin concentration was apparent after stimulation with sucrose and saccharin. In conclusion, the current data suggest that the sweeteners sucrose and saccharin activate a CPIR even when applied to the oral cavity only.