- Function like peptide hormones or steroid hormones depending on structure and regulation
- Catecholamines act like peptide hormones because they bind extracellularly
- Thyroid Hormones act like steroid hormones because they bind intracellularly
- Most, however, don’t just diffuse through the membrane like steroid hormones do
Common Amino Acid Derived Hormones
- Catecholamines: derived from tyrosine
- Thyroid Hormones: derived from tyrosine
- Serotonin: derived from tryptophan