What's the difference between peptide hormones and peptide neurotransmitters?

Question

What's the difference between peptide hormones and peptide neurotransmitters?

Answer 1

Simpler than you would guess: one is a hormone, one is a neurotransmitter.

The peptide designation refers more to the size of the molecule than the function.  Proteins are described as "polypeptide."  Basically, a peptide is a chunk of bonded amino acids that doesn't qualify as a protein.

If you need a crash course in hormones and neurotransmitters, the Wikipedia articles are decent, if short.

Neurotransmitters:

http://en.wikipedia.org/wiki/Neurotransm...

Hormones:

http://en.wikipedia.org/wiki/Hormone

Peptide hormones:

http://en.wikipedia.org/wiki/Peptide_hor...

Neuropeptide:

http://en.wikipedia.org/wiki/Neuropeptid...

Answer 2

Hormones are released into the blood stream, and so have long range action. Neurotrasmitters are more local.