Steroidal hormones are lipid-soluble hormones derived from cholesterol. They are produced mainly by the adrenal cortex, gonads (ovaries and testes), and placenta. Because they are lipid-soluble, they easily cross cell membranes and exert their action by regulating gene transcription.
Characteristics of Steroidal Hormones
- Derived from cholesterol
- Lipophilic and easily cross cell membranes
- Bind intracellular or nuclear receptors
- Longer duration of action compared to peptide hormones
- Circulate in blood bound to plasma proteins
Classification of Steroidal Hormones
Steroidal hormones are broadly classified into:
- Glucocorticoids
- Mineralocorticoids
- Sex hormones (androgens, estrogens, progestins)
1. Glucocorticoids
Produced mainly by the adrenal cortex (zona fasciculata). They regulate metabolism and help the body respond to stress.
Main Hormone
- Cortisol (hydrocortisone)
Functions
- Increase glucose production (gluconeogenesis)
- Anti-inflammatory action
- Immunosuppression
- Regulate protein and fat metabolism
- Help body cope with stress
Synthetic Glucocorticoids
- Prednisolone
- Dexamethasone
- Betamethasone
- Triamcinolone
Therapeutic Uses
- Asthma and allergic reactions
- Autoimmune diseases
- Inflammatory conditions (arthritis)
- Adrenal insufficiency
- Dermatological disorders
Side Effects
- Weight gain
- Hyperglycemia
- Osteoporosis
- Peptic ulcers
- Suppression of HPA axis
2. Mineralocorticoids
Produced by the adrenal cortex (zona glomerulosa). They regulate electrolyte and water balance.
Main Hormone
- Aldosterone
Functions
- Increases sodium and water reabsorption
- Promotes potassium and hydrogen ion excretion
- Maintains blood pressure and fluid balance
Synthetic Mineralocorticoids
- Fludrocortisone
Uses
- Addison’s disease
- Adrenal insufficiency
3. Sex Hormones
a) Androgens
Male sex hormones produced by testes and adrenal cortex.
Main Hormone
- Testosterone
Functions
- Development of male secondary sexual characteristics
- Muscle growth and strength
- Spermatogenesis
Clinical Uses
- Male hypogonadism
- Delayed puberty
Side Effects
- Acne
- Mood swings
- Liver toxicity (with synthetic androgens)
b) Estrogens
Female sex hormones produced by ovaries, adrenal cortex, and placenta.
Main Hormones
- Estradiol
- Estrone
- Estriol
Functions
- Development of female secondary sexual characteristics
- Regulation of menstrual cycle
- Bone health
Synthetic Estrogens
- Ethinyl estradiol
- Diethylstilbestrol
Uses
- Hormone replacement therapy
- Oral contraceptives
c) Progestins
Hormones that maintain pregnancy and regulate the menstrual cycle.
Main Hormone
- Progesterone
Synthetic Progestins
- Norethindrone
- Medroxyprogesterone acetate
- Levonorgestrel
Uses
- Oral contraceptives
- Hormone replacement therapy
- Management of menstrual disorders
Mechanism of Action of Steroidal Hormones
Steroids bind to intracellular receptors → the receptor-hormone complex enters the nucleus → binds DNA → alters gene transcription → produces long-lasting physiological effects.
Clinical Importance
- Control inflammation (glucocorticoids)
- Maintain fluid balance (mineralocorticoids)
- Regulate reproductive functions (sex hormones)
- Used in contraception, infertility treatment, and hormone replacement therapy
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