On the basis of their chemical nature, hormones are divided into four groups :
1. Amino acid derivatives : These hormones are formed from amino acids e.g. epinephrine, norepinephrine etc.
2. Peptide derivatives : These are of derived from peptide, polypeptide and proteins e.g. insulin, glucagon, pituitary, hypothalamic hormones etc
3. Iodothryonines derivatives : e.g. thyroid hormones.
4. Steroid hormones : These are derived from steroids just as cholesterol e.g. testosterone, progestrone etc.