Comparecontrast the following classes of hormones by identif

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