Vasopressin: It is also called anti - diuretic hormone (ADH). It controls the reabsorption of water and electrolytes from the distal tubules (DT) or nephrons in kidney. It is called diuresis. It reduces the loss of water. When the ADH is less secreted it.leads to the excess loss of water and dehydration occurs. The kidney is unable to conserve water. This disorder is called diabetes insipidus.