Vasopressin is the mediator of a remarkable regulatory system for the conservation of water. The hormone is released by the posterior pituitary whenever water deprivation causes an increased plasma osmolality or whenever the cardiovascular system is challenged by hypovolemia and/or hypotension. In humans, vasopressin acts primarily in the renal collecting duct, increasing the permeability of the cell membrane to water and permitting water to move passively down an osmotic gradient across the collecting duct into the extracellular compartment.
Vasopressin also is a potent vasopressor whose name was chosen in recognition of its vasoconstrictor action. Vasopressin is a neurotransmitter; among its actions in the CNS are apparent roles in the secretion of ACTH and in the regulation of the cardiovascular system, temperature, and other visceral functions. Vasopressin also may play a role in hemostasis by promoting the release of coagulation factors by the vascular endothelium and increasing platelet aggregation.
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...