|Background:||Human growth hormone (hGH, somatotropin) is a single chain polypeptide Human growth hormone (hGH, somatotropin) is a single chain polypeptide hormone, synthesized, stored and secreted by somatotroph cells found in the anterior pituitary gland.
Serum hGH concentrations exhibit marked variation over 24 hours due to episodic bursts of hGH secretion and prominent circadian and sleep-associated variations in hGH release. Also, many environmental and metabolic factors, including nutrient intake, exercise, physical stress, depression, trauma and age influence hGH secretion and clearance and therefore its serum concentration. Because basal hGH concentrations are often undetectable using conventional RIA or IRMA immunoassays ultra sensitive hGH assays have been developed which allow discrimination among populations that were previously undetectable.
Due to the low levels and pulsatile secretion of hGH, stimulation tests are the most common method of evaluating hGH deficiency. These involve stimulating the pituitary somatotrophs to secrete hGH in response to a pharmacological stimulus (insulin, clonidine, arginine, L-dopa, growth hormone releasing hormone and propranolol may be used). Failure to achieve a peak level of hGH release is indicative of insufficiency.
Acromegaly (hGH excess) can be assessed by performing a suppression test on an individual with elevated hGH. This involves creating a hyperglycaemic state in the patient by the administration of glucose and measuring the change in hGH levels. Failure to suppress hGH by hyperglycaemia is indicative of excess. hGH measurements are used in the diagnosis and treatment of disorders involving the anterior lobe of the pituitary gland.
|Reference Ranges:||Male: up to 1ng/mL (2.6mIU/L)
Female: up to 10ng/mL (26 mIU/L)
|Specimen Requirements:||Sample type:
|Turnaround Time:||1 week|