Question

The synthesis of vasopressin is done by
(A) Hypothalamus
(B) Kidney
(C) Anterior pituitary
(D) Posterior pituitary

Answer 1

Hint: Vasopressin is a nonapeptide hormone that is synthesized by neurons. Nonapeptide hormone is a hormone that is made up of a chain of nine amino acids.

Complete answer:
Hypothalamus is a small structure situated in the brain. It is neuroendocrine in function. It links the nervous and endocrine systems of the body. It consists of neurons that synthesize a number of hormones like corticotropin-releasing hormone (CRH), dopamine, somatostatin, gonadotropin releasing hormone (GnRH) and vasopressin.
Vasopressin is synthesized for the reabsorption of water from kidneys. After its synthesis, vasopressin leaves hypothalamus and enters the posterior pituitary gland. Vasopressin is stored in the posterior pituitary gland till it is required by the body. When the need for vasopressin in the body arises, it is released by the posterior pituitary gland into the bloodstream from where it reaches its target organs (kidneys).
Kidney is the main organ of excretion. Kidneys synthesize three hormones namely erythropoietin, calcitriol and renin. Kidneys are the target organs (organs where a hormone shows its effect) of vasopressin, but it is not synthesized by kidneys.
Anterior pituitary synthesizes seven different hormones on receiving signals from hypothalamus. Hormones like TSH (Thyroid Stimulating Hormone) and GH (Growth Hormone) are produced in anterior pituitary. It does not produce vasopressin.
Posterior pituitary does not synthesize any hormone. It stores and releases two hormones synthesized in hypothalamus. These hormones are vasopressin and oxytocin.
Thus, vasopressin is synthesized by hypothalamus but stored and released by posterior pituitary.

So the correct answer is Option (A) Hypothalamus.

Note:
Vasopressin is known by different names like Antidiuretic hormone (ADH), Arginine Vasopressin (AVP) or argipressin. It plays an important role in maintaining water and sodium homeostasis, blood pressure and kidney function.