Ghrelin

Definition

Ghrelin is a peptide hormone produced mainly in the stomach that stimulates appetite and plays a significant role in energy balance. It is often referred to as the 'hunger hormone' because it signals the brain to induce feelings of hunger and promotes food intake. Ghrelin also has other functions, including influencing the release of growth hormone and regulating glucose metabolism.

5 Must Know Facts For Your Next Test

1. Ghrelin levels typically increase before meals and decrease after eating, which aligns with its role in stimulating appetite.
2. This hormone can also affect other physiological processes, such as enhancing gastric motility and influencing reward pathways in the brain related to food consumption.
3. Ghrelin is not only produced in the stomach but also in smaller amounts in other tissues, including the brain and pancreas.
4. Research suggests that ghrelin may play a role in sleep regulation and could be linked to sleep deprivation and its effects on appetite.
5. Imbalances in ghrelin levels have been associated with conditions such as obesity and eating disorders, indicating its importance in energy homeostasis.

Review Questions

• How does ghrelin influence appetite regulation in the human body?
  • Ghrelin influences appetite regulation primarily by signaling the hypothalamus to stimulate feelings of hunger. When the stomach is empty, ghrelin levels rise, prompting an increase in appetite and food intake. After eating, ghrelin levels decrease, which helps to signal satiety. This intricate feedback mechanism plays a crucial role in maintaining energy balance.
• Discuss the relationship between ghrelin and leptin in the context of energy balance.
  • Ghrelin and leptin work together to maintain energy balance in the body, where ghrelin promotes hunger while leptin signals satiety. When fat stores are low, ghrelin levels rise to encourage food intake, whereas when fat stores increase, leptin levels rise to suppress appetite. An imbalance between these two hormones can contribute to obesity and other metabolic disorders, highlighting their opposing roles in hunger regulation.
• Evaluate how changes in ghrelin levels could impact overall health and weight management strategies.
  • Changes in ghrelin levels can significantly impact overall health and weight management strategies by influencing hunger cues and energy expenditure. For instance, elevated ghrelin levels may lead to increased appetite and overeating, complicating weight loss efforts. Conversely, strategies aimed at reducing ghrelin activity or enhancing leptin sensitivity could be beneficial for promoting healthy weight management and preventing obesity-related health issues. Understanding these hormonal interactions is vital for developing effective dietary and lifestyle interventions.

Related terms

Leptin: A hormone produced by adipose (fat) tissue that helps to regulate energy balance by inhibiting hunger, essentially signaling to the brain that the body has enough energy stored.

Hypothalamus: A region of the brain that plays a crucial role in maintaining homeostasis, including regulating hunger and energy expenditure through various hormones, including ghrelin.

Obesity: A medical condition characterized by excessive body fat accumulation, often linked to an imbalance between energy intake and expenditure, which can involve hormonal influences like ghrelin.