Why ADH is called antidiuretic hormone? What is the condition if this secretion is less?

Explanation

Vasopressin or antidiuretic hormone (ADH) is a peptide hormone which promotes reabsorption of water and eletrolytes by distal tubules of nephron and thereby reduces loss of water through urine. Hence it is called as anti diuretic hormone. It also causes constriction of blood vessels when released in large amount and increases blood pressure. ADH deficiency causes Diabetes insipidus which induces the production of large amount of urine.