What is the Origin of Orexigenic Peptides?

The term is derived from Greek roots: "orexis" meaning appetite or desire, and "genic" meaning producing. They are literally "appetite-producing" substances. The discovery of the first key orexigenic peptide, Neuropeptide Y (NPY), provided a crucial insight into the powerful central control mechanisms governing hunger and satiety. Ghrelin is another prominent example, often termed the "hunger hormone."

What is the Mechanism of Orexigenic Peptides?

These peptides are predominantly released from the gut or synthesized in specific hypothalamic nuclei, particularly the arcuate nucleus. Ghrelin, for example, is secreted by the stomach when empty, traveling to the hypothalamus where it activates neurons that express NPY and Agouti-related peptide (AgRP). This activation drives the sensation of hunger and reduces the body's metabolic rate, prompting the organism to seek and consume calories to restore energy balance.

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Orexigenic Peptides

Meaning

Orexigenic peptides are a group of hormonal and neuropeptide messengers that primarily function to stimulate appetite, promote food-seeking behavior, and decrease energy expenditure. These molecules act as powerful signals to the central nervous system, communicating a state of energy deficit or hunger to initiate feeding. The balance between these peptides and their anorexigenic counterparts is essential for the physiological regulation of body weight.