The molecule ghrelin is an acylated peptide that stimulates the release of growth hormone from the pituitary gland. Masamitsu Nakazato and collegues from Miyazaki Medical College, Kiyotake, Japan report in 11 January Nature that ghrelin mediates feeding and probably has a function in growth regulation, by stimulating feeding and release of growth hormone.

Nakazato et al injected ghrelin into the brains of rats, and found that the animals ate more and gained weight (Nature 2001, 409:194-198). Conversely, a ghrelin blocker robustly suppressed feeding. Further investigations of ghrelin's function will help understanding the physiological feeding mechanisms and may facilitate the discovery of a treatment for eating disorders.