Abstract
Leptin is a hormone primarily produced in adipose cells ; it regulates food intake, energy expenditure, and body weight mainly via activation of the hypothalamic functional leptin receptor (Ob-Rb).Recently, we found that the peripheral taste organ is also a target for leptin, where it acts on taste receptor cells via Ob-Rb expressed in these cells and specifically inhibits gustatory responses to sweet substances. Such selective sweet response inhibition by leptin was not observed in leptin receptordeficient db/db mice, suggesting that leptin may be a sweet-sensation modulator involved in the regulation of food intake. Here, we further examined potential links between leptin and sweet taste in humans. The present study reveals that recognition thresholds for sweet substances are tightly linked with circulating leptin. The tight linkage between sweet taste thresholds and leptin levels was evident even in the restricted meal conditions with synchronized phase shifts of diurnal variations. This synchronization of diurnal variation in leptin levels and sweet taste recognition thresholds suggests a mechanistic connection between these two variables.
