Difference Between Adrenaline and Noradrenaline

Adrenaline vs Noradrenaline

Adrenaline and noradrenaline are extremely important hormones to maintain the basic functions of the body. The chemical makeup, place of action, and functions are different from each other in adrenaline and noradrenaline. It would be interesting to know that these two are referred differently in some parts of the world, as adrenaline is known as epinephrine and noradrenaline is known as norepinephrine in the United States. It is important to be aware about these hormones given the significance of their function in maintaining the stability of the body organ systems.


Adrenaline is one of the major hormones that are necessary to maintain the activities of an animal. In addition, adrenaline functions as a neurotransmitter. It is a type of monoamines known as Catecholamines synthesized in the adrenal gland medullaw. When adrenaline is secreted into the blood, the heart rate is increased, blood vessels are constricted, and the air passages are dilated. These result the animal to be at a highly alerted state known as fight-or-fight state. In simple terms, the animal becomes highly nervous when adrenaline is secreted into blood, and that causes to animal to fight against the threat or run away to save the life. Since this hormone has those properties, it is being used as a treatment for many medical conditions such as cardiac arrest, superficial bleeding, and deadly allergic reactions like anaphylaxis.

Adrenaline has great importance in ecology and other related biological aspects including wildlife biology and captive animal programs. That is because this hormone is released into blood under certain conditions viz. any stress causing effect. In captive animal programs, the release of this hormone is used as an indication to describe that the animal may be in stress for certain activities. In wildlife biology and management, adrenaline secretion in a particular group of animals could be observed at different viewing distances, so that the distance that causes the least excitement can be determined to observe them.


Noradrenaline is mainly a hormone as well as a neurotransmitter. Noradrenaline is a catecholamine, produced at the adrenal medulla, and it is secreted into the blood stream from there. However, it is important to know that the majority of the noradrenaline production in the body takes place in the neurons of the brain, which makes it more a neurotransmitter than a hormone. The places of body that noradrenaline being secreted are known as noradrenergic areas.

Noradrenaline functions as a stress hormone when it is secreted into the blood stream, as it increases the heart rate especially to cause increased blood supply to skeletal muscles. In addition, noradrenaline triggers the release of glucose from the energy stores of the body to extract a high amount of ATP from cellular respiration. Furthermore, noradrenaline affects parts of brain viz. amygdala where control of emotions and activities is maintained; instead, the fight-or-flight response is triggered. The function of noradrenaline as a neurotransmitter is important for the heart rate to increase.


What is the difference between Adrenaline and Noradrenaline?

• Chemical structures of these hormones / neurotransmitters are different from each other with the presence of a methyl group attached to nitrogen in adrenaline, but that is a hydrogen atom in noradrenaline.

• The activated parts of the body are different for the two with more receptors for adrenaline than for noradrenaline.

• The alpha effect of adrenaline is a very strong but beta effect is weak, whereas noradrenaline has a weak alpha effect.

• Adrenaline is mainly a hormone while noradrenaline is mainly a neurotransmitter.