This would be difficult to answer. I presume you are referring to the human intestinal tract. Levels would vary depending on age, size, probably sex as well, and also with the presence or absence of stimuli. Could you let me know what precisely you need to know and what for and I will see if I can help.

thank you for the answer. yes i am referring to the human intestinal tract. I need to know if nanomolar can be found or more, and be in contact with the microbiota.

You did not wrote anything about the outcome, sample methods or conditions for sampling.

Norepinephrine and epinephrine can most likely be found and measured in the nmol range in the gut. Be aware that the concentration of norepinephrine and epinephrine is higher on the arterial site of the vascular bed than on the venous site. I dont know the arterial/venous gradient for mesenterical vessels, but for forearm it is

epinephrine: 49/1

norepinephrine 4/1

Norepinephrine is most likely to be found on the venous site. If you want to measure changes, then norepinephrine is the way to go, as you can measure it on the venous site, which is way easier. Please be aware that surgery of the GI tract or acute venous puncture will increase NE and could be a source of error especially for basal levels.  An indwelling catheter and 20-30 min. of rest will give reasonable values for basal levels.

Please write if further clarification or help is needed.

Hi,

Could anyone  please advise me what can be used as the best method to measure norepinephrine variation in the gut of production mammals?

Thank you!

I will suggest you look into sampling of norepinephrine (NE) from a vena port catheter as done by these fellows in rats. Then use a commercially available kit to determine the concentration. There is other methods of measuring NE but they are rather complicated. Article Gut-derived norepinephrine plays an important role in up-reg...

This will give you the NE spillover from the gut and it will be a good start. It will very likely be associated with gut activity.

Your sources of error will be on the supply side as NE can be released from the heart and the gut so NEsupply = NEheart + NEgut

If you assume NEheart to be constant as in rest, then NE spillover measured on the venous site will be associated with NEgut

And yes, it has effect on gut microbiota. For instance, to express its virulence, the enterohemorrhagic E. coli uses the IA-3 QS system which is induced by the epinephrine/norepinephrine available in the intestine.