Leptin
- Leptin is a hormone that is secreted by fat storage cells known as adipose cells
- The concentration of leptin in the blood is controlled by the amount of adipose tissue in the body
- As we eat food over a period of time, adipose cells store fats in the form of lipids
- As adipose cells fill up, they secrete more leptin
- This leptin circulates in the blood and targets groups of cells in the hypothalamus that are responsible for controlling appetite
- It does this by binding to receptors in the membranes of these cells
- This inhibits appetite and causes the sensation of hunger to be suppressed, or stopped
- If food intake is low over a period of time, the lipid reserves in adipose cells are used up and the adipose cells become empty again
- As adipose cells empty and shrink, they secrete less leptin
- The suppression of appetite stops, and the sensation of hunger returns