UCN3 (urocortin 3) is a neuropeptide hormone belonging to the corticotropin-releasing hormone family that functions as a critical regulator of stress homeostasis and metabolic control 1. The protein acts as a selective agonist for corticotropin-releasing hormone receptor 2 (CRHR2), mediating stress responses and maintaining homeostatic balance after stress exposure 1. In pancreatic islets, UCN3 serves as a local inducer of somatostatin release from delta cells, providing negative feedback to modulate insulin and glucagon secretion, and represents a hallmark of functional beta cell maturation 2. UCN3 demonstrates potent anorexic effects, strongly inhibiting appetite regulation in animal models 3. In the cardiovascular system, UCN3 exerts protective effects including vasodilation, positive inotropic effects, and cardioprotection against ischemia-reperfusion injury 4. The protein plays important roles in behavioral regulation, with UCN3-expressing neurons in the perifornical hypothalamic area mediating stress-induced changes in infant-directed behavior 5. Dysregulation of the UCN3/CRHR2 axis is implicated in various stress-related clinical conditions including post-traumatic stress, cardiovascular disease, and other stress-related disorders, making it a potential biomarker for stress management 1.