Growth Hormone (GH)
GH is the pituitary hormone driving growth in childhood and metabolism in adults. Random readings are hard to interpret — the diagnostic tests are GH suppression (for excess) and GH stimulation (for deficiency).
What it measures
Growth hormone is released by the anterior pituitary in pulses, with the largest peaks during deep sleep and exercise. Between pulses serum GH can be near zero in healthy adults, so a random blood draw rarely confirms or excludes disease on its own. GH acts mostly indirectly through IGF-1 (made by the liver in response to GH); IGF-1 is much more stable in serum and is the preferred screening test. The diagnostic standard is provocative testing: oral glucose tolerance test to suppress GH (excess fails to suppress → acromegaly), or insulin/arginine stimulation (failure to rise → adult GH deficiency).
What a high value can mean
- Acromegaly / gigantism — pituitary adenoma secreting GH; bone, organ and soft-tissue overgrowth, often with insulin resistance.
- Stress, exercise, fasting, hypoglycaemia — physiological pulses that confound interpretation.
- Ectopic GH or GHRH-secreting tumours — rare.
- Some forms of diabetes — relative GH excess due to insulin resistance.
What a low value can mean
- Adult growth hormone deficiency — pituitary disease (surgery, irradiation, trauma, tumour); presents with reduced muscle mass, increased fat, low mood.
- Healthy adult between pulses — most common reason for an undetectable random level.
- Hypothyroidism — secondary suppression of GH axis.
When to discuss with a doctor
Random GH levels rarely lead directly to action — IGF-1 is the cleaner screen, and dynamic (suppression / stimulation) testing is the diagnostic standard. Symptoms that prompt evaluation include unexplained acral enlargement (rings tightening, shoe-size increasing in adulthood), jaw protrusion, snoring, hypertension and new diabetes (excess), or reduced energy, central obesity and low muscle mass after pituitary surgery (deficiency). Mediora.AI reports the value; acromegaly and adult-GHD diagnosis sits with endocrinology.