Steviol glycosides enhance pancreatic beta-cell function and taste sensation by potentiation of TRPM5 channel activity.
Philippaert K., Pironet A., Mesuere M., Sones W., Vermeiren L., Kerselaers S., Pinto S., Segal A., Antoine N., Gysemans C., Laureys J., Lemaire K., Gilon P., Cuypers E., Tytgat J., Mathieu C., Schuit F., Rorsman P., Talavera K., Voets T., Vennekens R.
Steviol glycosides (SGs), such as stevioside and rebaudioside A, are natural, non-caloric sweet-tasting organic molecules, present in extracts of the scrub plant Stevia rebaudiana, which are widely used as sweeteners in consumer foods and beverages. TRPM5 is a Ca(2+)-activated cation channel expressed in type II taste receptor cells and pancreatic β-cells. Here we show that stevioside, rebaudioside A and their aglycon steviol potentiate the activity of TRPM5. We find that SGs potentiate perception of bitter, sweet and umami taste, and enhance glucose-induced insulin secretion in a Trpm5-dependent manner. Daily consumption of stevioside prevents development of high-fat-diet-induced diabetic hyperglycaemia in wild-type mice, but not in Trpm5(-/-) mice. These results elucidate a molecular mechanism of action of SGs and identify TRPM5 as a potential target to prevent and treat type 2 diabetes.