ghrelin; ghrelin -27; ghrelin-28

Function

• ligand for growth hormone secretagogue receptor type 1 (GHSR)
• induces release of growth hormone from the pituitary separate from GHRH
• effects are probably synergistic with GHRH
• has an appetite-stimulating effect
• induces adiposity
• stimulates gastric acid secretion
• role in growth regulation
• when administered peripherally to rodents daily, caused weight gain by decreased fat utilization
• activates the mesolimbic reward system for food & alcohol

Structure

• ghrelin circulates in acylated & deacylated forms, which affect appetite
• O-octanoylation or O-decanoylation is essential for ghrelin activity
• O-decanoylated forms Ghrelin-27-C10 & Ghrelin-28-C10 differ in the length of the carbon backbone of the carboxylic acid bound to Ser-26
• a small fraction of ghrelin, ghrelin-28-C10:1
• may be modified with a singly unsaturated carboxylic acid

Expression

• derived from precursor appetite regulating hormone
• the principal site of synthesis in stomach
• serum levels increased by fasting, reduced by feeding
• high-intensity exercise superior to moderate-intensity exercise for reducing ghrelin levels & modifying hunger
• other tissues compensate for the loss of ghrelin synthesis in the stomach following gastrectomy

More general terms

• appetite-regulating hormone

Additional terms

• obestatin (hexarelin)

Database

• OMIM: https://mirror.omim.org/entry/605353
• UniProt: http://www.uniprot.org/uniprot/Q9UBU3.html