Growth hormone, also called GH or somatotropin, is an important hormone produced by the pituitary gland that acts on the growth of children and adolescents and also participates in the body's metabolism processes.
This test is done with the dosage in blood samples collected in the laboratory and is usually requested by the endocrinologist when there is suspicion of the lack of GH production, especially in children who present a growth below the expected, or the excess production of it, common in gigantism or acromegaly.
The use of GH as a medicine is indicated when there is a deficiency in the production of this hormone, in children or adults, as indicated by the doctor. To learn more about how it is used, prices and effects of growth hormone, check out the label for the hormone GH.
What is it for
The GH test is requested if you suspect:
- Dwarfism, which is the deficiency of growth hormone in children, causing short stature. Understand what it is and what can cause dwarfism; Adult GH deficiency, caused by sub-normal GH production, which leads to symptoms such as fatigue, increased fat mass, decreased lean mass, decreased exercise capacity, reduced bone density and increased risk of developing cardiovascular diseases; Gigantism, characterized by the excess of GH secretion in the child or adolescent, causing an exaggerated growth. Understand how to identify and treat gigantism; Acromegaly, which is a syndrome caused by overproduction of GH in adults, causing changes in the appearance of the skin, hands, feet and face. See also the differences between acromegaly and gigantism;
The lack of GH in the body can have several causes, such as genetic diseases, brain changes, such as tumors, infections or inflammations or due to the side effect of a chemo or brain radiation, for example. The excess of GH usually happens due to a pituitary adenoma.
How is done
The measurement of the GH hormone is done by analyzing blood samples in the laboratory and is done in 2 ways:
- Basal GH dosage: it is done with at least 6 hours of fasting for children and 8 hours for adolescents and adults, which analyzes the amount of this hormone in the morning blood sample; GH stimulation test (with Clonidine, Insulin, GHRH or Arginine): it is done with the use of drugs that can stimulate GH secretion, in case of suspected lack of this hormone. Next, blood GH concentrations are analyzed after 30, 60, 90 and 120 minutes of using the drug.
The GH stimulation test is necessary because the production of the GH hormone by the body is not uniform, and can be interfered by several factors, such as fasting, stress, sleep, playing sports or when the amount of glucose in the blood falls. Thus, some of the drugs used are Clonidine, Insulin, Arginine, Glucagon or GHRH, for example, which stimulate or inhibit the production of the hormone.
In addition, the doctor may also order other tests, such as the measurement of hormones such as IGF-1 or IGFBP-3 protein, which change with GH variations: MRI scan of the brain, to assess changes in the pituitary gland, too it can be useful to identify the cause of the problem.
