Lac-Phe induces hypophagia by inhibiting AgRP neurons in mice.

N-Lactoyl-phenylalanine (Lac-Phe) is a lactate-derived circulating metabolite that reduces feeding and obesity, but the molecular mechanisms that underlie the metabolic benefits of Lac-Phe remain unknown. Here we show that Lac-Phe directly inhibits hypothalamic neurons that express Agouti-related protein (AgRP), resulting in an indirect activation of anorexigenic neurons in the paraventricular nucleus of the hypothalamus (PVH). Both AgRP inhibition and PVH activation are required to mediate Lac-Phe-induced hypophagia. Lac-Phe-mediated inhibition of AgRP neurons occurs through activation of the ATP-sensitive potassium (KATP) channel, whereas inhibition of the KATP channel blunts the effects of Lac-Phe to suppress feeding. Together, these results reveal the molecular and neurobiological mechanisms by which Lac-Phe mediates metabolic improvements and suggest this exercise-induced metabolite might have therapeutic benefits in various human diseases.