Endogenous Peptide
A peptide that is naturally produced within the human body. Many therapeutic peptide drugs are based on or identical to endogenous peptides such as oxytocin, vasopressin, and glucagon, while others are synthetic analogues designed to improve upon the natural molecule's pharmacological properties.
Technical Context
The human body produces hundreds of endogenous peptides serving as hormones (GLP-1, GHRH, GnRH, somatostatin), neurotransmitters (substance P, enkephalins, endorphins), paracrine signals (growth factors), and antimicrobial defence molecules (defensins, cathelicidins). Some therapeutic peptides are bio-identical to their endogenous counterparts — synthetic oxytocin and vasopressin have identical amino acid sequences to the natural hormones. Others are modified analogues designed to improve upon natural pharmacological properties. Understanding the endogenous peptide landscape is essential for evaluating the safety profile of therapeutic peptides, as bio-identical compounds may have more predictable effects.