Salivary PYY: A putative bypass to satiety

Peptide YY _3-36 is a satiation hormone released postprandially into the bloodstream from L-endocrine cells in the gut epithelia. In the current report, we demonstrate PYY _3-36 is also present in murine as well as in human saliva. In mice, salivary PYY _3-36 derives from plasma and is also synthesized in the taste cells in taste buds of the tongue. Moreover, the cognate receptor Y2R is abundantly expressed in the basal layer of the progenitor cells of the tongue epithelia and von Ebner's gland. The acute augmentation of salivary PYY _3-36 induced stronger satiation as demonstrated in feeding behavioral studies. The effect is mediated through the activation of the specific Y2 receptor expressed in the lingual epithelial cells. In a long-term study involving diet-induced obese (DIO) mice, a sustained increase in PYY _3-36 was achieved using viral vector-mediated gene delivery targeting salivary glands. The chronic increase in salivary PYY _3-36 resulted in a significant long-term reduction in food intake (FI) and body weight (BW). Thus this study provides evidence for new functions of the previously characterized gut peptide PYY _3-36 suggesting a potential simple and efficient alternative therapeutic approach for the treatment of obesity.