Ghrelin – Role in the Regulation of Body Weight, Metabolic and Reproductive Disturbances

Issue: 4/2010

Author: Maria Orbetzova, Mitko Mitkov, Blagovest Pehlivanov

Abstract:

Ghrelin has profound orexigenic, adipogenic, and somatotropic properties, increasing food intake and body weight. Secreted predominantly from the stomach, ghrelin is the natural ligand for the growth hormone secretagogue- receptor (GHS-R) in the pituitary gland, thus fulfilling the criteria of a brain–gut peptide. The brain–gut axis is the effector of anabolism by regulating growth, feeding, and metabolism via vagal afferent mediating ghrelin signaling. However, the wide tissue distribution of ghrelin suggests that it may have other functions as well. Several studies propose that ghrelin could have an important function in glucose homeostasis and insulin release, independent of GH secretion. Low plasma ghrelin levels are associated with elevated fasting insulin levels and insulin resistance, suggesting both physiological and pathophysiological roles for ghrelin. Recent data also suggest an intrinsic abnormality of ghrelin regulation in PCOS not attributable to obesity or insulin resistance alone. The mechanisms linking abnormal ghrelin regulation with PCOS and reproductive disturbances should be a focus for future research.