Leptin and the Sweet Release

Diabetic mice harboring mutations in or defective expression of the leptin receptor become obese. Although these mice ingest greater quantities of food, Kamai et al . present evidence that leptin suppresses responses to sweet stimuli. Injection of leptin into control mice resulted in reduced responses of taste-associated nerves to sucrose and saccharin; however, responses to sour, salty, and bitter stimuli remained unchanged. Leptin administration led to the hyperpolarization of taste receptor-bearing cells, as measured by increased outward K + currents, presumably resulting from the closure of K + channels. Taste cells appeared to express the leptin receptor, suggesting that leptin can target taste receptors, and specifically can function to suppress the response to sweet stimuli. Kawai, K., Sugimoto, K., Nakashima, K., Miura, H., and Ninomiya, Y. (2000) Leptin as a modulator of sweet taste sensitivities in mice. Proc . Natl . Acad . Sci . U . S . A . 97 : 11044 -11049. [Abstract] [Full Text]