UPSC CSE Prelims 2006
Reason (R): A person with Diabetes insipidus suffers from excess secretion of vasopressin.
Assertion (A) is true. Diabetes insipidus is a disorder characterized by the kidneys' impaired ability to reabsorb water, leading to the excretion of large volumes of dilute urine (polyuria). This excessive fluid loss results in dehydration, which in turn triggers intense thirst (polydipsia) as a compensatory mechanism.
Reason (R) is false. Diabetes insipidus arises from either a deficiency in the production or secretion of vasopressin (antidiuretic hormone, ADH) from the posterior pituitary gland (central diabetes insipidus) or the kidneys' inability to respond to vasopressin (nephrogenic diabetes insipidus). Therefore, the condition is associated with insufficient or ineffective vasopressin action, not its excess secretion.
Given that Assertion (A) is true and Reason (R) is false, option C is the correct answer.
Option A is incorrect because Reason (R) is false.
Option B is incorrect because Reason (R) is false.
Option D is incorrect because Assertion (A) is true.