Action in which gut peptides exert influence beyond the gut, such as on the brain, liver, pancreas, and fatty tissues, by traveling through the blood circulation and binding on the cell’s surface receptor to exert their action on the target organs. For instance, cholecystokinin hormone (CCK) produced in the gut binds to receptors in the brain and causes neurotransmitter release that affects behavior and emotional regulation (Ballaz et al., 2017).