Antidiuretic hormone (ADH)

Definition

A polypeptide hormone produced by the hypothalamus and released by the posterior pituitary gland, increasing renal water reabsorption.

How it works

The antidiuretic hormone (ADH), also known as vasopressin or arginine-vasopressin, is synthesized in the hypothalamus and stored in the posterior pituitary gland. ADH release is stimulated by increased plasma osmolality or decreased blood volume. ADH acts by binding to V2 receptors in the renal collecting tubule, activating a cascade that inserts aquaporins into the apical membrane, increasing water permeability. This action favors water reabsorption and concentrates urine. Inadequate ADH causes central diabetes insipidus with massive polyuria.

Role

Regulates renal water reabsorption and maintains osmolality and blood volume.

Examples

• Release during dehydration
• Suppression during overhydration
• Concentration of urine during fever
• Increase with intense exercise

Recommendations

Understand that ADH functions optimally with adequate hydration. Consult a healthcare professional in case of symptoms of central diabetes insipidus (extreme thirst, polyuria).

Key takeaway

ADH is the key hormonal regulator of renal water conservation.

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