Physiology, Obesity Neurohormonal Appetite And Satiety Control
Anthony Y. Yeung, Prasanna Tadi
Abstract
The feelings of appetite and satiety involve complex interactions between hormones from the gastrointestinal tract to the hypothalamus and subsequent feedback. Within the hypothalamus are specific regions where hormones interact in producing sensations of appetite and satiety, leading to food consumption or a feeling of fullness. Through the interactions of ghrelin and leptin, the hypothalamus can regulate the sensation of and satiety, leading to energy homeostasis. Ghrelin, which is termed the hunger hormone, was initially discovered through its receptor, growth hormone secretagogue receptor (GHS-R), before first explaining its role as a growth-hormone-releasing peptide. Leptin was discovered primarily as a signal in regulating body weight. However, the roles of these hormones in regulating appetite and satiety were not explicitly known until research showed a correlation between a rise in plasma levels of ghrelin before meals and a subsequent decrease in plasma levels of ghrelin after meals and a subsequent change in plasma leptin levels. Together, ghrelin and leptin signals regulate our sensations of and satiety by sending signals to different nuclei within the hypothalamus for food intake. Imbalance and dysregulation of these hormones can have drastic effects on the body's energy homeostasis.