Growth hormone (GH), also called somatotropin, is a hormone produced by the pituitary, a small gland located at the base of the brain.

GH plays a key role in regulating growth, especially during childhood and adolescence. It influences the body's ability to build muscle, break down fat, and maintain a healthy metabolism.

It also controls protein production and supports bone development.

Growth hormone is often measured to assess growth-related problems in children or metabolic disorders in adults. Abnormal levels may indicate pituitary disorders or other health conditions that affect growth and metabolism.

A growth hormone test is prescribed when there is a suspicion of abnormal production of this hormone in the body, often indicated by symptoms related to growth, metabolism, or bone health.

Common cases where testing may be recommended include:

• Unexplained short stature or slow growth in children.
• Delayed puberty or developmental problems.
• Symptoms of acromegaly (enlargement of facial and hand bones) in adults.
• Fatigue and weakness due to potential hormonal imbalances.
• Low bone density or osteoporosis.
• Abnormal cholesterol levels or lipid metabolism disorders.

To measure growth hormone levels, a venous blood test is usually done. As GH levels fluctuate throughout the day, special test methods can be used to get accurate results.

Specific tests

• Stimulation test : This test assesses whether the body is making enough GH. The patient may be asked to fast for 10 to 12 hours prior to the test. A solution, such as insulin or arginine, is injected, and blood samples are taken at specific intervals to monitor the response.
• Suppression test : This test measures whether the body is making too much GH. After a fast, glucose solution is administered. Blood samples are taken to check how GH production is inhibited by glucose.

Preparations

Besides fasting, it may be advisable to avoid certain medications or stressful activities before the test, as these can influence hormonal levels.

Normal levels of growth hormone vary by age and gender:

Kids

• Up to 6 years: 0.10-6.20 ng/ml
• Ages 6 to 17 (boys): 0.05-11.00 ng/ml
• Ages 6 to 17 (girls): 0.05-17.30 ng/ml

Adults

• Men: 0-3.00 ng/ml
• Women: 0-8.00 ng/ml

Note: Normal measurement units and ranges may vary depending on the laboratory and the methods used.

High levels of growth hormone

High GH levels may indicate hyperactivity in the pituitary gland.

Common causes:

• Pituitary adenoma : Benign tumor of the pituitary gland causing an overproduction of GH.
• Acromegaly : A condition in adults characterized by thickening of bones, especially in the face, hands, and feet.
• Gigantism : A condition in children resulting in excessive height and large body due to overproduction of GH during childhood.
• Hypokalemia : Low potassium levels can interfere with GH production.

Recommendations:

• Perform regular follow-up and imaging tests to assess the size of the pituitary gland.
• Talk to a healthcare professional about potential treatments to lower hormone levels.
• Adopt a balanced diet and a healthy lifestyle to manage the symptoms of acromegaly or gigantism.
• Consider surgery if there is a pituitary tumor.

Low levels of growth hormone

Low GH levels can lead to disorders that affect physical growth, development, and metabolism.

Common causes:

• Pituitary dwarfism : Insufficient GH production leading to significantly slowed growth.
• Growth retardation : Slower than normal growth in children due to pituitary problems.
• Cushing's syndrome : Overproduction of cortisol can interfere with GH production.
• Hypopituitarism : Pituitary dysfunction leading to insufficient production of several hormones, including GH.

Recommendations:

• Consider hormonal therapies prescribed by a health professional to increase GH levels.
• Regularly monitor the growth and development of children.
• Maintain a diet rich in proteins and nutrients that are essential to support normal growth.
• Engage in physical activity to promote better growth and bone density.

For concerns related to growth hormone, it is recommended that you consult:

• Endocrinologist : Specialist in hormonal disorders.
• Pediatrician : For children with growth problems.
• Internist : For adults with metabolic or hormonal disorders.

Regular follow-up and appropriate management are essential to effectively manage growth hormone imbalances and maintain optimal health.