Compare/contrast the following classes of hormones by identifying three similarities and four differences among/between them. In addition, be able to list several specific examples of each. AMINE vs. PEPTIDE vs. STEROID Solution Three similarities between the three hormones- 1. Being hormones, the site of synthesis and the site of action of all the three hormones are different. 2. They are all organic molecules and rich in carbon and hydrogen. 3. They are all released directly into the blood stream. Differences Peptide Steroid Amine Composition Made of few to many amino acids(3-200), synthesized from mRNA Derived from cholesterol (from pregnenolone, a steroid precursor) Derived from amino acids tyrosine or tryptophan Solubility in lipid bilayer Not soluble soluble Not soluble Nature Hydrophillic with cell surface receptors( except- thyroid hormones are lipid soluble) Lipophillic with intracellular receptors Hydrophillic with cell surface receptors Mode of Action Through secondary messengers like cAMP, cGMP etc by cascading effect Once inside the cell it binds DNA and modifies transcription Through binding to beta adrenergic receptors, by secondary messengers (signal transduction) or calcium or phosphoinositides Examples ADH, calcitonin, Insulin, Pituitary Hormones (LH,FSH, ACTH, TSH,GH) Estrogen, Progesterone, testosterone, cortisol Epinephrine, nor epinephrine, melatonin, dopamine Peptide Steroid Amine Composition Made of few to many amino acids(3-200), synthesized from mRNA Derived from cholesterol (from pregnenolone, a steroid precursor) Derived from amino acids tyrosine or tryptophan Solubility in lipid bilayer Not soluble soluble Not soluble Nature Hydrophillic with cell surface receptors( except- thyroid hormones are lipid soluble) Lipophillic with intracellular receptors Hydrophillic with cell surface receptors Mode of Action Through secondary messengers like cAMP, cGMP etc by cascading effect Once inside the cell it binds DNA and modifies transcription Through binding to beta adrenergic receptors, by secondary messengers (signal transduction) or calcium or phosphoinositides Examples ADH, calcitonin, Insulin, Pituitary Hormones (LH,FSH, ACTH, TSH,GH) Estrogen, Progesterone, testosterone, cortisol Epinephrine, nor epinephrine, melatonin, dopamine.

1. Compare/contrast the following classes of hormones by identifying three similarities and four
differences among/between them. In addition, be able to list several specific examples of each.
AMINE vs. PEPTIDE vs. STEROID
Solution
Three similarities between the three hormones-
1. Being hormones, the site of synthesis and the site of action of all the three hormones are
different.
2. They are all organic molecules and rich in carbon and hydrogen.
3. They are all released directly into the blood stream.
Differences
Peptide
Steroid
Amine
Composition
Made of few to many amino acids(3-200), synthesized from mRNA
Derived from cholesterol (from pregnenolone, a steroid precursor)
Derived from amino acids tyrosine or tryptophan
Solubility in lipid bilayer
Not soluble
soluble
Not soluble
Nature
Hydrophillic with cell surface receptors( except- thyroid hormones are lipid soluble)
Lipophillic with intracellular receptors
Hydrophillic with cell surface receptors
Mode of Action
Through secondary messengers like cAMP, cGMP etc by cascading effect
Once inside the cell it binds DNA and modifies transcription
Through binding to beta adrenergic receptors, by secondary messengers (signal transduction) or
calcium or phosphoinositides
Examples
ADH, calcitonin, Insulin, Pituitary Hormones (LH,FSH, ACTH, TSH,GH)
Estrogen, Progesterone, testosterone, cortisol
Epinephrine, nor epinephrine, melatonin, dopamine

2. Peptide
Steroid
Amine
Composition
Made of few to many amino acids(3-200), synthesized from mRNA
Derived from cholesterol (from pregnenolone, a steroid precursor)
Derived from amino acids tyrosine or tryptophan
Solubility in lipid bilayer
Not soluble
soluble
Not soluble
Nature
Hydrophillic with cell surface receptors( except- thyroid hormones are lipid soluble)
Lipophillic with intracellular receptors
Hydrophillic with cell surface receptors
Mode of Action
Through secondary messengers like cAMP, cGMP etc by cascading effect
Once inside the cell it binds DNA and modifies transcription
Through binding to beta adrenergic receptors, by secondary messengers (signal transduction) or
calcium or phosphoinositides
Examples
ADH, calcitonin, Insulin, Pituitary Hormones (LH,FSH, ACTH, TSH,GH)
Estrogen, Progesterone, testosterone, cortisol
Epinephrine, nor epinephrine, melatonin, dopamine