Vasopressin
Hormone regulating water balance and blood pressure.
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Vasopressin, also known as antidiuretic hormone (ADH), arginine vasopressin (AVP), or argipressin, is a peptide hormone synthesized from the AVP gene in neurons of the hypothalamus. It is converted to AVP and transported to the posterior pituitary, where it is stored and released into the circulation in response to increased plasma osmolality or decreased arterial blood volume. Vasopressin plays a critical role in regulating body fluid tonicity by increasing water reabsorption in the kidneys and can also constrict arterioles to raise blood pressure.
Lore & Background
Vasopressin is synthesized as a prohormone in magnocellular neurosecretory neurons of the paraventricular and supraoptic nuclei of the hypothalamus. It travels down axons through the infundibulum within neurosecretory granules, stored in Herring bodies, and is released from the posterior pituitary into the blood. The primary stimulus for secretion is increased plasma osmolality, monitored by the hypothalamus; decreased arterial blood volume can also trigger release even in the presence of hypoosmolality.
Reader's Guide
Vasopressin is essential for maintaining body fluid homeostasis. Its main action in the kidney is to increase water permeability of the collecting ducts by inserting aquaporin-2 channels, allowing solute-free water reabsorption and producing concentrated urine. It also increases urea permeability in the inner medullary collecting duct and stimulates sodium chloride reabsorption in the thick ascending limb via NKCC2 activation. Beyond renal effects, vasopressin constricts arterioles, raising peripheral resistance and blood pressure.
In the brain, it may influence social behavior, pair bonding, and maternal responses. Its short half-life (16–24 minutes) necessitates rapid regulation. The structure is a nonapeptide with a disulfide bridge, closely related to oxytocin.
Did You Know?
- Ethanol reduces vasopressin secretion by blocking voltage-gated calcium channels in neurohypophyseal nerve terminals.
- Vasopressin induces differentiation of stem cells into cardiomyocytes and promotes heart muscle homeostasis.
- The amino acid sequence of arginine vasopressin is Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly-NH2.
Frequently Asked Questions
What is Vasopressin?
Vasopressin is a nine-amino-acid peptide hormone (a nonapeptide) produced by hypothalamic neurons and released from the posterior pituitary into the bloodstream. It serves as the body's principal signal for conserving water and maintaining vascular tone.
What are Vasopressin's main jobs in the body?
Its two headline roles are antidiuresis—prompting the kidneys to reabsorb more water—and vasoconstriction, where it tightens arteriolar smooth muscle to support blood pressure. Together these keep plasma osmolality and circulating volume within a narrow physiological range.
Which receptors does Vasopressin interact with?
It signals through three distinct receptor subtypes: V1a on vascular smooth muscle, V1b in the anterior pituitary, and V2 on renal collecting-duct cells. Each subtype triggers a different downstream response, allowing one hormone to coordinate both vascular and renal effects.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Vasopressin (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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