Key Laboratory of Yunnan Province for Biomass Energy and Environment Biotechnology,                                                                      Kunming 650500, China

Cholecystokinin (CCK) acts on the peripheral or central nervous system and generates a large number of satiety signals, regulating food intake and body mass. CCK also plays a role in promoting digestion and nutrient absorption throughout the gastrointestinal tract. There are many hormones that affect the secretion of CCK, such as leptin, ghrelin and insulin. Because CCK is related to energy metabolism, it also affects the occurrence of cancer and other diseases to a certain extent. In a word, CCK has many functions, and its role in appetite regulation is crucial. The peripheral mechanism of CCK involved in appetite regulation has been studied thoroughly, while the central mechanism needs further study. It is worth noting that CCK is also related to the occurrence of a variety of diseases. Therefore, CCK in the study of energy metabolism related diseases deserves more in-depth research. The fundamentals, the method of secretion, the variables influencing CCK secretion, and its critical function in appetite regulation are covered in this article, laying the groundwork for future studies on the energy metabolism of mammals by combining hormones like CCK.