Temperature as a Metabolic Signal Linking Neural and Endocrine Circuits to Energy Homeostasis

Ambient temperature is a continuous environmental input that affects energy homeostasis through integrated physiological programs. In mammals, thermal cues detected by cutaneous and visceral sensors are conveyed through spinal, vagal, and sympathetic pathways. They are complemented by circulating mediators from the gut, liver, and adipose tissue. These signals converge on brainstem-hypothalamic networks, including the preoptic area and arcuate nucleus, to coordinate feeding behavior, thermogenesis, vasomotor tone, and endocrine outputs. Recent circuit-mapping and single-cell approaches have refined the cellular logic governing the distinct architectures of cold- and heat-defense programs. This review synthesizes these advances to illustrate how a plastic effector network maintains systemic energy homeostasis. Finally, we highlight the translational implications of these thermosensory mechanisms for treating obesity and type 2 diabetes.