What is the definition or description of: leptin hormone?

Adipose hormone: It is an adipose (fat cells)- derived hormone that plays a key role in regulating energy intake and energy expenditure, including appetite/hunger and metabolism.

Leptin is a protein : Leptin is a protein that's made in the fat cells, circulates in the bloodstream, and goes to the brain. Leptin tells your brain that you have enough energy stored in your fat cells to engage in normal, relatively expensive metabolic processes, when your leptin levels are low, food is even more rewarding. When your leptin levels are high, that's supposed to extinguish the reward system so that you.