The<unk> s (or gut<unk> s) constitute a group of<unk> s secreted by enteroendocrine cells in the stomach, pancreas, and small intestine that control various functions of the digestive organs. Later studies showed that most of the gut peptides, such as secretin, cholecystokinin or substance P, were found to play a role of neurotransmitters and neuromodulators in the central and peripheral nervous systems. Enteroendocrine cells do not form glands but are spread throughout the digestive tract. They exert their autocrine and paracrine actions that integrate<unk>  function.
Gastrointestinal hormone
Hormone
Xenohormone
Neurohormone
Local hormone
Sex hormone
Thyroid hormones
Lymphokine