Based on your knowledge of signal amplification, which type of chemical messenger can have relatively small concentrations within the bloodstream and still get a large response?

Lipophobic is not soluble in non-polar solvents or  in lipids of chemical substances or any parts of molecules. It is the type of chemical messenger that still get a large response despite of having a relatively small concentration within the bloodstream. It is in contrast of the lipophilic.

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