The arcuate nucleus is a collection of neurons present in the hypothalamus. Some arcuate neurons contain dopamine and inhibit the release of prolactin by the pituitary. Other neurons contain neuropeptide Y (NPY) and affect hunger. When activated, these neurons can produce ravenous eating. These neurons are probably regulated by glucose, insulin, and leptin. Thus, arcuate neurons are responding to information on whether the body has sufficient calories (and probably other nutrients).

The nucleus is located in the mid-hypothalamus in the most ventral part of the 3rd ventricle near the entrance of the infundibular recess. Its neurons are in close contact with the ependyma