Epinephrine and Nonepinephrine : What is the difference?

[JerryClower]

What is the difference between what these two hormones do? I have read answers but they were way too complex to understand. Will someone please tell me the difference?

 

[DanP]

What is the difference between what these two hormones do? I have read answers but they were way too complex to understand. Will someone please tell me the difference?

I don't know how "deep" must be your understand of the differences. For a cursory understanding will suffice to know that

- both mediate similar effects
- nor-adrenaline is almost totally liberated as a neurotransmitter from symphatethic nerve terminals, hence it is not a "true" hormone (look-up adrenergic transmission in a textbook)
- adrenaline is secreted by the adrenal medulla, and is a true hormone in every sense of the word
- both are refereed as cathecolamines, both being amine of a cathecol nucleus

 

[JerryClower]

Wise answer, my friend.

 

[AyazM]

How "similar" both tend to act is only a function of how much you want to delve into this topic. For records, just realize their actions are more dissimilar rather than similar, although the wide spectrum of their actions constitute the functioning of sympathetic nervous system.

Epinephrine is actually a derivative of norepinephrine with an extra methyl group (-CH₃). BOTH are released into blood stream as hormones, although the concentration of epinephrine is much greater than norepinephrine because of its greater release from adrenal medulla compared to its parent compound. Adrenals are unique because they contain Catechol-O-Methyl Transferase that can methylate norepinephrine whereas the nerve terminals lack this enzyme.

Just one more important point: Epinephrine acts on all Alpha and Beta receptors whereas norepinephrine is devoid of Beta₂ effects.