Salivary PYY: A Putative Bypass to Satiety

Abstract

Peptide YY3-36 is a satiation hormone released postprandially into the bloodstream from L-endocrine cells in the gut epithelia. In the current report, we demonstrate PYY3-36 is also present in murine as well as in human saliva. In mice, salivary PYY3-36 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 PYY3-36 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 PYY3-36 was achieved using viral vector-mediated gene delivery targeting salivary glands. The chronic increase in salivary PYY3-36 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 PYY3-36 suggesting a potential simple and efficient alternative therapeutic approach for the treatment of obesity.

Adult-onset PYY overexpression in mice reduces food intake and increases lipogenic capacity

“…PYY is primarily released from endocrine L cells of the lower gastrointestinal tract in proportion to the amount of calories ingested (Adrian et al, 1986, Batterham et al, 2002and Ekblad and Sundler, 2002. A recent study shows that PYY is also synthesized by cells in the taste buds of the tongue, and this has important implications for the induction of satiety (Acosta et al, 2011). In the circulation, two forms of PYY exist; the full-length PYY1-36, and the truncated form, PYY3-36, which is cleaved from PYY1-36 by the specific cell surface enzyme dipeptidyl peptidase-IV (DPPIV) (Mentlein, 1999 andUnniappan et al, 2006).…”

The Use of Electrophoresis for the Study of Saliva Involvement in Ingestive Behavior

“…Hormones and peptides related to ingestive behaviour, known to be present in saliva are present in relatively low amounts (e.g. PYY, leptin and ghrelin) [12,103], and in this context their analysis can also be benefit from some of the advantages in CE. Nonetheless, this is an issue deserving further attention.…”

Dipeptidyl Peptidase-IV Activity and Neuropeptide Y in the Mouth: The Relationship with Body Composition and the Impact of Carbohydrates

“…DPP-IV is present in the blood and as a component of saliva in the mouth. Two possible sources of DPP-IV in the mouth are exosomes released by the salivary glands [2,3] and/ or by transport from capillaries or secretion into the gingival cervicular fluid [4]. Although controversial, some research posits that changes in proteins in the saliva may mirror the blood [5][6][7][8].…”

“…In particular, The Y 2 receptors are present in the basal epithelial layer of the tongue [11,12] and are sensitive to the DPP-IV-cleaved forms of Neuropeptide Y (NPY ) and peptide YY (PYY ) and contribute to feelings of satiety when activated [4,13,14] through its connection to the hypothalamic satiety centers [15].…”

“…Evidence suggests that the mouth may play an important role in the physiological response to food [4,13]. It is well understood that certain foods effect the feeling of satiety [19][20][21][22], but it is unknown if salivary DPP-IV is part of this connection between the mouth and the brain.…”