Source of norepinephrine is?
Tyrosine REF: Lehninger Principles of Biochemistry 4th Edition page 440, 678, and 859 "Tyrosine gives rise to a family of catecholamines that includes dopamine, norepinephrine, and epinephrine" "Norepinephrine is synthesized by a series of enzymatic steps in the adrenal medulla and postganglionic neurons of the sympathetic nervous system from the amino acid tyrosine"
Phenylalanine
Alanine
Tyrosine
Tryptophan