Question

Vasopressin stimulates reabsorption of water and reduction of urine secretion. Vasopressin is also called
A. Synovial fluid
B. Neurotransmitter
C. Antidiuretic hormone
D. Growth regulating substance

Answer 1

Hint: Vasopressin is a hormone secreted by hypothalamus gland in the form of peptide prohormone and then converted to arginine vasopressin (AVP) in neurons or nerve cells. It sometimes gets released directly into the brain and may play an active role in behavioural activities, pair bonding and can raise blood pressure as well.

Complete answer:
Vasopressin is a hormone which is produced in hypothalamus in neurons. Main functions of this hormone are:
> In kidney tubules, nephrons are present which filter blood and helps in the purification of the blood. This hormone helps in reabsorption of solute-free water into the blood circulation back.
> Arterioles increases the peripheral vascular resistance and they increase blood pressure in arteries. Thus, arginine vasopressin (AVP) constricts the arterioles.
> Some arginine vasopressin (AVP) gets released directly into the brain from hypothalamus and help in maintaining some behavioural changes, sexual activities, pair bonding and others.
> Vasopressin hormone is also known as antidiuretic hormone (ADH) or argipressin.

Thus, we can say that, Vasopressin is also called as an antidiuretic hormone (ADH) or argipressin and option ‘C’ is the correct answer.

Note: There are some factors which affects the release of this vasopressin hormone:
> Ethanol: In rats, AVP blocks the voltage-gated calcium channels which present neurohypophyseal nerve terminals of the rats. Thus, presence of alcohol or ethanol leads to reduction in the secretion of the AVP hormone.
> Cortisol also reduces or inhibits the production of vasopressin hormone.
> Atrial natriuretic peptide also blocks or inhibits the production of vasopressin hormone.