Question

Are hormones always proteins?

Answer 1

No, not all hormones are proteins.

Explanation:

In humans there are 4 chemical classes of hormones.

A) Amino acid derivatives
eg. Melatonin, Thyroxine.

B). Protein derivatives :- these are further divided into
1) small peptide hormones. eg Insulin
2) glycoprotein hormones. eg Thyroid stimulating hormone

C) Fatty acid derivatives or Eicosanoids
eg. Prostaglandins

D) Cholesterol derivatives or Steroid hormones
eg Testosterone, Cortisol.