Fig. 37. Simplified schematic representation of some of the regulatory factors and pathways involved in the regulation of appetite and satiety. Circulating factors derived from fat, pancreas, liver and the gastrointestinal tract converge on the hypothalamus and/or brainstem to orchestrate a series of responses that promote increased appetite, decreased energy expenditure, activation of mesolimbic reward centers and reduce circulating thyroid hormone levels. Note similarities of target regions in the brain by several regulatory factors, particularly for AGRP/NPY and -MSH/CART neurons in the hypothalamic arcuate nucleus. The endocannabinoid system exerts regulatory effects on neurons in multiple regions of the brain. Other regions of the brain including the amygdala, hippocampus, and prefrontal cortex also have important roles in the regulation of eating. ARC= arcuate nucleus, DMN= dorsomedial nucleus, DVC= dorsal vagal complex, LH= lateral hypothalamus, PVN= paraventricular nucleus, SNS=sympathetic nervous system, VMN= ventromedial nucleus.