Ghrelin - Characterization, regulation of synthesis, release and possible role in reproduction

Abstract

Ghrelin is a peptide, composed of 28-amino acid residues, with a characteristic modification by n-octanoid acid, covalently linked to the serine-3. Considering a genomic position, the gene of ghrelin in humans is located on chromosome 3p25-26. Major source of ghrelin seems to be the stomach, but other tissues and organs such as: the small intestine, pancreas, pituitary gland, arcuate nucleus of the hypothalamus, kidney, placenta, lungs, testis, ovaries and adrenal glands, were reported to synthesize this peptide also. Body weight was proved to be superior to food intake for ghrelin regulation and an impaired hormone response to feeding status appeared in obese individuals. Based on experimental data, which show that ghrelin and its receptor are expressed in normal human ovary and testis, it has been proposed that ghrelin acting as either an endocrine and/or a paracrine signal, may play a major role in the endocrine network that integrates energy balance and reproduction.