White Adipose as a Target for the Gastrointestinal Hormones

Excessive fat deposition in the form of obesity is now a major health problem worldwide leading to an increased risk of a number of diseases, including type II diabetes, coronary heart disease and cancer. Adipose tissue was originally thought to be used by the body solely as an energy store. In recent years, increases in the prevalence of obesity and ongoing research, has shown that lipid storage is not the only function of white fat. The discovery of leptin, which was followed by the identification of other protein factors, termed ‘adipokines’, secreted by white adipose tissue (WAT), indicated that WAT is major endocrine organ. The gastrointestinal tract is the portal for the entry of dietary nutrients and a number of intestinal hormones such as glucagon-like peptide-1 (GLP-1) and glucosedependent insulinotropic polypeptide (GIP), known as incretin’s, and ghrelin, are involved in their absorption and storage. Recently, it was found that the gene precursor of ghrelin encoded another secreted and bioactive peptide named obestatin, and was shown to have actions opposite to that of ghrelin.