Ghrelin

Definition

Ghrelin is a peptide hormone primarily produced by the stomach that plays a crucial role in regulating appetite and energy balance. It is often referred to as the 'hunger hormone' because it stimulates appetite, promotes fat storage, and influences energy expenditure, connecting metabolism and growth regulation with the body's energy needs and thermoregulation.

5 Must Know Facts For Your Next Test

1. Ghrelin levels increase before meals and decrease after eating, signaling hunger to the brain.
2. It is produced mainly in the stomach but can also be found in smaller amounts in the intestines, pancreas, and brain.
3. Research shows that ghrelin not only stimulates appetite but may also play a role in promoting growth hormone release from the pituitary gland.
4. Ghrelin's effects on appetite and metabolism can be influenced by various factors, including sleep patterns, stress, and body weight.
5. Imbalances in ghrelin levels have been linked to obesity, eating disorders, and metabolic syndromes.

Review Questions

• How does ghrelin interact with other hormones to regulate appetite and energy balance?
  • Ghrelin interacts with hormones like leptin to maintain energy homeostasis. While ghrelin promotes hunger and fat storage, leptin signals satiety and reduces appetite. The balance between these hormones is crucial for regulating food intake and energy expenditure, ensuring that the body meets its energy demands while preventing excessive weight gain or loss.
• Discuss the physiological mechanisms by which ghrelin influences metabolism and growth.
  • Ghrelin influences metabolism by signaling the hypothalamus to increase appetite and food intake while also promoting fat storage. It stimulates the release of growth hormone from the pituitary gland, which plays a vital role in tissue growth and metabolism. This dual action highlights how ghrelin not only affects hunger but also contributes to overall metabolic processes and growth regulation in the body.
• Evaluate how changes in ghrelin levels could contribute to obesity and metabolic disorders.
  • Changes in ghrelin levels can significantly impact appetite regulation and energy balance. In individuals with obesity, studies show that ghrelin levels may be altered, leading to an increased appetite despite adequate or excessive calorie intake. This dysregulation contributes to metabolic disorders by promoting continuous weight gain and making it challenging for individuals to lose weight, indicating that managing ghrelin levels could be a potential strategy for addressing obesity-related health issues.

Related terms

leptin:

A hormone produced by adipose (fat) tissue that helps to regulate energy balance by inhibiting hunger, thus opposing the effects of ghrelin.

hypothalamus: A region of the brain that plays a key role in regulating appetite and energy homeostasis, integrating signals from ghrelin and other hormones to control food intake.

metabolism: The set of life-sustaining chemical reactions that involve converting food into energy, with hormones like ghrelin influencing these processes by regulating hunger and energy utilization.