Peptide Hormones vs Steroid Hormones

Peptide hormones

Come from amino acids, small polypeptides

Peptide hormones

Are water soluble

Peptide hormones

Bind to membrane receptors

Peptide hormones

Require a second messenger to reach and identify their targets

Peptide hormones

Target existing proteins inside the cell, thus cause post-translational modifications

Peptide hormones

Examples include: Epi., norepi., melatonin, insulin, OT, TSH

Peptide hormones

Translation

• mRNA > Protein

Steroid hormones

Come from fatty acids, glycerol, cholesterol, ad lipids

Steroid hormones

Are lipid soluble

Steroid hormones

Bind to intracellular receptors

Steroid hormones

Specifically bind to a specific piece of DNA called the hormone responsive element (HRE)

Steroid hormones

Directly influences the rate of transcription

Steroid hormones

Examples include: E2, T, prostaglandins, leukotrienes, calcitriol

Steroid hormones

Transcription

• DNA > mRNA