GH is a polypeptide (191 amino acids) originating in the anterior pituitary. Its metabolic effects are primarily anabolic. It promotes protein conservation and engages a wide range of mechanisms for protein synthesis. It also enhances glucose transport and facilitates the buildup of glycogen stores. Testing is used in the diagnosis and treatment of various forms of inappropriate growth hormone secretion.
Normal range:
0 " “7 years: 1 " “13.6 ng/mL
7 " “11 years: 1 " “16.4 ng/mL
11 " “15 years: 1 " “14.4 ng/mL
15 " “19 years: 1 " “13.4 ng/mL
Adult male: 0 " “4 ng/mL
Adult female: 0 " “18 ng/mL
Interpretation
Increased In
Pituitary gigantism
Acromegaly
Laron dwarfism (defective GH receptor)
Ectopic GH secretion (neoplasm of the stomach and lung)
Malnutrition
Renal failure
Cirrhosis
Stress, exercise, prolonged fasting
Uncontrolled diabetes mellitus
Anorexia nervosa
Decreased In
Pituitary dwarfism
Hypopituitarism
Adrenocortical hyperfunction
Limitations
Random levels provide little diagnostic information.
GH levels vary throughout the day, making it difficult to define a reference range or to judge an individuals status based on single determination.
Periods of sleep and wakefulness, exercise, stress, hypoglycemia, estrogens, corticosteroids, l-dopa, and factors influence the rate of growth hormone secretion.
Because of its similarity to prolactin and placental lactogen, earlier GH immunoassays were often plagued with falsely high values in pregnant and lactating women.