Ghrelin: update 2003

Ghrelin is a recently described peptide hormone that is secreted by endocrine cells in the gastrointestinal tract. Although its initial discovery was as a novel growth hormone secretagogue, it has been found to regulate feeding behavior by modulating expression levels of orexigenic peptides in the hypothalamus. Ghrelin has been implicated in the coordination of energy balance and weight regulation, and its dysregulation may be important in obesity. Ghrelin also has several other physiologic actions besides potential regulation of food intake that are described in this brief review.