Regulation of feeding and therapeutic application of bioactive peptides

Obesity and obesity-related diseases, such as diabetes mellitus and dyslipidemia, are worldwide pandemics; therefore, studies have been conducted energetically to elucidate the mechanism of obesity and develop anti-obesity drugs. Robust progress in the peptide chemistry and molecular biology has identified many peptides that regulate appetite and energy metabolism over the past dozen years. Several drugs, such as analogs or receptor agonists of anorectic peptides, have been developed. Overall, peptide-related drugs have powerful anti-obesity effects with fewer adverse effects than previous anti-obesity drugs. Liraglutide, a glucagon-like peptide-1 receptor agonist, was first used as an antidiabetic drug, and then high-dose liraglutide was used as an anti-obesity drug. Several candidates have been developed to explore their anti-obesity effects. Additionally, hybrid peptides consisting of two or more peptide sequences with strong anorectic effects have been designed. Here, we review peptides that are important for feeding regulation in terms of their mechanisms of action, interactions, and clinical application as anti-obesity drugs.