The vasopressins are peptide hormones consisting of nine amino acids (nonapeptides). They include arginine vasopressin (AVP; anti-diuretic hormone, ADH) and oxytocin. They are synthesized in the hypothalamus from a precursor and released from stores in the posterior pituitary into the blood stream. One of the most important roles of vasopressins is the regulation of water retention in the body. Oxytocin is important in uterine contraction during birth. The vasopressins act via AVP and oxytocin receptors. These are connected to G proteins which act as second messengers and convey the signal inside the cell.
van Leeuwen, FW,