3. Derivatives of the amino acid tyrosine(Wk 氨酸), secreted by thyroid(thyroxine and triodothyronine) adrenal medullae(epinephrine and norepinephrine 今004m中 CHS H NH NH3+ Tyrosine Epinephrine12 3. Derivatives of the amino acid tyrosine (酪 氨酸）, secreted by thyroid (thyroxine and triiodothyronine) adrenal medullae (epinephrine and norepinephrine)