Assertion : Diabetes insipidus is marked by excessive urination and too much thirst of water. Reason : Anti-diuretic hormone (ADH) is secreted by the posterior lobe of pituitary gland.

Step-by-step solution

Antidiuretic hormone ( ADH ) or vasopressin is secreted from posterior pituitary gland. It is released in response to a fall in the water content of blood plasma and leads to an increase in the permeability to water of the distal and collecting tubules of the nephron. Deficiency or hyposecretion of ADH results in diabetes insipidus. Diabetes insipidus is characterised by micturating dilute urine several times a day which results in excessive thirst (polydipsia) and dehydration.