Home > Peptide hormone

Like other proteins, peptide hormones are synthesized from amino acids according to an mRNA template, which is itself synthesized from a DNA template inside the cell's nucleus. Peptide hormone precursors (pre-prohormones) are then processed in several stages, typically in the endoplasmic reticulum, including removal of the N-terminal signal sequence and sometimes glycosylation, resulting in prohormones.

These prohormones often contain superfluous amino acid residues that were needed to direct folding of the hormone molecule into its active configuration but have no function once the hormone folds. Specific endopeptidases in the cell cleave the prohormone just before it is released into the blood stream, generating the mature hormone form of the molecule. Mature peptide hormones then diffuse through the blood to all of the cells of the body, where they interact with specific receptorIn biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm that binds to a specific factor (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. As all receptorss on the surface of their target cells.

Notable peptide hormones

• atrial-natriuretic peptide (ANP) or atrial natriuretic factor (ANF)
• antidiuretic hormoneAntidiuretic hormone ADH , or arginine vasopressin AVP , is a peptide hormone produced by the hypothalamus, and stored in the posterior pituitary gland. ADH acts on the kidneys, concentrating the urine by promoting the reabsorption of water and salt into, also called vasopressin
• growth hormoneGrowth hormone is a polypeptide hormone secreted by the anterior pituitary gland which stimulates growth and cell reproduction in humans and other vertebrate animals. This article describes human growth hormone physiology, with brief mentions of the disea
• insulincarbon; green: oxygen; blue: nitrogen; pink: sulphur. The blue/purple ribbons denote the skeleton [-N-C-C-]n in the protein's amino acid sequence H-[-NH-CHR-CO-]n-OH where R is the part protruding from the skeleton in each amino acid. Insulin ( Latin insu
• oxytocinOxytocin is a nine amino acid peptide hormone synthesized in magnocellular neurosecretory cells in the hypothalamus and released by the posterior lobe of the pituitary gland. Oxytocin is often bound to neurophysin (a carrier protein) as shown in the inset
• somatostatinSomatostatin is a hormone. Precisely it is mixture of two peptides, one built of 14 amino acids, the other of 28. Somatostatin is secreted not only by cells of the hypothalamus but also by so called delta cells of stomach, intestine and pancreas. It binds

Many neurotransmitterA neurotransmitter is a type of molecule that carries signals between neurons (nerve cells) at synapses in the nervous system. Neurotransmitters may be either excitatory ( EPSPs) or inhibitory ( IPSPs). That is, they may foster the initiation of a nerve is are secreted and released in a similar fashion to peptide hormones, and some peptides may be used as neurotransmitters in the nervous system in addition to acting as hormones when released into the blood.