Diabetes insipidus occur due to lack of:

# Diabetes insipidus occur due to lack of:

A. Insulin

B. Antidiuretic hormone

C. ACTH

D. Thyroxin

The correct answer is B. Antidiuretic hormone.

The neurohypophysis， or posterior pituitary， is formed by axons that originate in large cell bodies in the supraoptic and paraventricular nuclei of the hypothalamus. It produces two hormones: ( 1 ) arginine

vasopressin (AVP)， also known as antidiuretic hormone， and (2) oxytocin. AVP acts on the renal tubulω to reduce water loss by con centrating the urine. Oxytocin stimulates postpartum milk letdown in response to suckling. A deficiency of AVP secretion or action causes diabetes insipidus (DI)，a syndrome characterized by the production of large amounts of dilute urine. Exιessive or inappropriate AVP production impairs urinary water excretion and predisposes to hyponatremia if water intake is not reduced in parallel with urine output.

Reference: Harrison's Principles of Internal Medicine, 19th Edition, Page no: 2274

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