Growth Hormone (GH) — also called somatotropin — is a protein-based hormone produced and secreted by the anterior pituitary gland (adenohypophysis). It plays a key role in:
- Promoting growth during childhood and adolescence
- Regulating metabolism and tissue repair throughout life
🧠 How Is GH Regulated?
GH secretion is controlled by the hypothalamus, which releases two hormones:
| Hypothalamic Hormone | Effect on GH |
|---|---|
| GHRH (Growth Hormone-Releasing Hormone) | Stimulates GH release |
| Somatostatin (also called GHIH) | Inhibits GH release |
Growth hormone is secreted in pulses, especially during:
- Deep sleep
- Exercise
- Fasting
- Stress
💡 What Does GH Do?
📏 In Children:
- Stimulates growth of bones and cartilage
- Increases height and physical development
- Promotes organ and muscle growth
💪 In Adults:
- Helps maintain muscle mass
- Supports bone density
- Aids in fat metabolism
- Supports tissue repair and recovery
Most of GH’s growth-promoting effects are indirect and occur through a hormone called IGF-1 (Insulin-Like Growth Factor 1), which is produced by the liver in response to GH.
🔬 GH’s Metabolic Effects:
| Effect | Description |
|---|---|
| ⬆️ Increases | Protein synthesis, lean muscle mass |
| ⬇️ Decreases | Fat stores (lipolysis), especially belly fat |
| 🧃 Promotes | Glucose production in liver (can increase blood sugar) |
🧪 What Is GH Measured or Used For?
Doctors may test GH (or IGF-1) to:
- Investigate growth delays or gigantism in children
- Diagnose acromegaly or GH deficiency in adults
- Monitor pituitary tumors
- Guide GH therapy (in children or adults with deficiency)
📉 Too Little GH (GH Deficiency):
In Children:
- Poor growth (short stature)
- Delayed puberty
- Increased fat, especially around the waist
In Adults:
- Fatigue
- Decreased muscle mass
- Poor exercise tolerance
- Depression or anxiety
- Increased body fat
Causes:
- Pituitary damage
- Genetic mutations
- Brain trauma or tumors
📈 Too Much GH (GH Excess):
In Children (before growth plates close):
- Gigantism: Abnormally tall stature, enlarged hands/feet
In Adults (after growth plates close):
- Acromegaly: Enlarged hands, feet, jaw, nose, tongue
- Joint pain, thickened skin
- High blood pressure
- Risk of diabetes and heart disease
Causes:
- Usually a pituitary adenoma (benign tumor)
💊 GH Therapy (Recombinant Human GH):
Approved uses:
- GH deficiency in children or adults
- Turner syndrome
- Chronic kidney disease with growth failure
- Prader-Willi syndrome
- Small for gestational age (SGA) with no catch-up growth
Note: GH is sometimes misused by athletes or bodybuilders to increase muscle or reduce fat, but non-medical use is illegal and risky.
🧠 Summary Table:
| Feature | Description |
|---|---|
| Full name | Growth Hormone (GH), aka Somatotropin |
| Produced by | Anterior pituitary gland |
| Controlled by | GHRH (stimulates), Somatostatin (inhibits) |
| Main effects | Growth, cell regeneration, metabolism |
| Works through | IGF-1 from liver |
| Deficiency leads to | Stunted growth, low energy, muscle loss |
| Excess leads to | Gigantism (kids), Acromegaly (adults) |