antidiuretic hormone

A hormone of the posterior pituitary gland that encourages resorption of water by acting on the epithelial cells of the distal portion of the renal tubule. It raises blood pressure by its effect on the peripheral blood vessels and exerts an antidiuretic effect (antifacultative resorption of water in the renal tubules). An absence of antidiuretic hormone H causes diabetes insipidus.

A hormone produced in the hypothalamus and secreted by the posterior pituitary gland. ADH stimulates reabsorption of water through the distal convoluted tubules and collecting ducts of the kidney, resulting in less water being excreted in the urine, thus conserving water. Intense exercise is usually associated with an increase in ADH secretion so that plasma volume levels may be maintained, minimizing the risk of dehydration during periods of heavy sweating.

The noun has one meaning:

Meaning #1: hormone secreted by the posterior pituitary gland (trade name Pitressin) and also by nerve endings in the hypothalamus; affects blood pressure by stimulating capillary muscles and reduces urine flow by affecting reabsorption of water by kidney tubules
  Synonyms: vasopressin, ADH, Pitressin