Ghrelin, Hormone That Stimulates Appetite, Found To Be Higher In PWS

By Edmund F. Funai, M.D.
Yale University School of Medicine

Ghrelin is a hormone that binds to a similar receptor as growth hormone. While it is not growth hormone, it may affect growth in humans by stimulating appetite. It is produced largely in the stomach, and may work on the brain.

Previous studies examined the effects of intravenous ghrelin on appetite and food intake, and found energy consumption increased 28 percent during ghrelin infusion (resulting in ghrelin levels approximately two times higher than fasting) compared with saltwater (placebo) infusion. Ghrelin concentrations are higher during starvation and increase with weight loss. Therefore, ghrelin may signal conservation of energy to prevent further weight loss and restore usual body weight. It is known that ghrelin levels are higher in PWS adults.

Andrea M. Haqq and colleagues recently published a study in The Journal of Clinical Endocrinology & Metabolism (88(1):174 –178) that examined ghrelin in PWS children. While the study was small, involving only 13 PWS subjects, it found that fasting ghrelin levels were three- to four-fold higher in children with PWS, compared to both normal weight children and children with various reasons for obesity. While some of the differences were not statistically different from each other, this study may provide a clue that obesity is PWS is at least partly related to excess ghrelin production.

Currently, there are no FDA-approved drugs that block the effects of ghrelin. However, the weight-loss industry is a multi-billion dollar business. If research continues to be promising, especially in non-PWS adults, we may see a ghrelin blocker from a major pharmaceutical company in the next 5-7 years, hopefully sooner.