Peptide hormones and steroid hormones are two main types of hormones in the body.
They differ in their structure, how they act, and where they bind.
Here’s a explanation:
1. Peptide Hormones
- Made of amino acids (small protein-like molecules).
- They are water-soluble, so they cannot pass through cell membranes.
- They bind to receptors on the surface of target cells.
- After binding, they trigger a signal inside the cell (using second messengers like cAMP).
- Their effects are fast but short-lived.
Examples:
- Insulin
- Glucagon
- Growth hormone
- Oxytocin
2. Steroid Hormones
- Made from cholesterol (a type of fat).
- They are fat-soluble, so they can pass through cell membranes easily.
- They bind to receptors inside the cell (in the cytoplasm or nucleus).
- They directly change gene activity and control protein production.
- Their effects are slower but long-lasting.
Examples:
- Estrogen
- Testosterone
- Cortisol
- Aldosterone
In short:
- Peptide hormones → made of amino acids, act on cell surface, work fast.
- Steroid hormones → made from cholesterol, act inside cells, work slowly but last longer.