Hgh sentence example
Iatrogenic CJD is very rare and most cases have resulted from hGH treatment or human dura mater grafts.
Growth hormone, secreted by... referred to as human growth hormone, secreted by... referred to as human growth hormone or " HGH, " it.. .
Taking HGH can repair the physiology of the old cell, and cause it to rejuvenate thus reversing aging.
Human growth hormone (hGH) (somatotropin) is produced by somatotropes in the anterior pituitary gland.
Somatotropin (hGH) is secreted by somatotropes in the anterior pituitary gland.Advertisement
When blood glucose levels fall, GHRH triggers the secretion of stored hGH.
As blood glucose levels rise, hGH secretion is turned off by GHIH activity.
This feedback loop, along with the effects of eating and exercise, is responsible for the fluctuating levels of hGH throughout the day.
Because of its critical role in producing hGH and other hormones, a dysfunctional pituitary gland will often lead to altered growth.
Dwarfism (very small stature) can be due to underproduction of hGH, lack of IGH-I, or a flaw in target tissue response to either of these growth hormones.Advertisement
Overproduction of hGH or IGH-I, or an exaggerated response to these hormones, can lead to gigantism or acromegaly, both of which are characterized by a very large stature.
Gigantism is the result of hGH overproduction in early childhood leading to a skeletal height up to 8 feet (2.5 m) or more.
Acromegaly results when hGH is over-produced after the onset of puberty.
In this condition, the epiphyseal plates of the long bones of the body do not close, and they remain responsive to additional stimulated growth by hGH.
Somatrotropin (hGH) is measured in the clinical laboratory to identify hGH deficiency in adolescents with short stature, delayed sexual maturity, and other growth or development abnormalities.Advertisement
The somatotropin test also aids in documenting the excess hGH production responsible for gigantism or acromegaly, and confirms underactivity or overproduction of the pituitary gland (hypopituitarism or hyperpituitarism, respectively).
However, due to variable secretion of hGH, as well as hGH production in response to stress, exercise, or other factors, random assays are not an adequate determination of hGH deficiency.
To obtain more accurate readings, a blood sample can be drawn one to one-and-a-half hours after sleep (hGH levels increase during sleep), or strenuous exercise can be performed for 30 minutes before blood is drawn.
The hGH levels at the end of an exercise period are expected to be maximal.
The somatomedin C test is usually ordered to help detect pituitary abnormalities, hGH deficiency, and acromegaly.Advertisement
Also called insulin-like growth factor (IGF-1), somatomedin C is considered a more accurate reflection of the blood concentration of hGH because such variables as time of day, activity levels, or diet do not influence test results.
Somatomedin C is part of a group of peptides, called somatomedins, through which hGH exerts its effects.
Because it circulates in the bloodstream bound to long-lasting proteins, it is more stable than hGH.
Levels of somatomedin C do depend on hGH levels, however, and typically somatomedin C levels will be low when hGH levels are deficient.
Abnormally low levels of somatomedin C will require further investigation, so doctors may perform the hGH stimulation test to diagnose hGH deficiency.Advertisement
The hGH stimulation test, also called hGH provocation test, insulin tolerance, or arginine test, is performed to test the body's ability to produce human growth hormone and to confirm suspected hGH deficiency.
A normal patient can have low hGH levels, but if hGH is still low after stimulation, a more definitive diagnosis can be made.
The test involves creating a condition of insulin-induced hypoglycemia (via intravenous injection of insulin) to stimulate production of hGH and corticotropin secretion as well.
A substance called hGH-releasing factor has also been used for hGH stimulation.
This approach is believed to be more accurate and specific for hGH deficiency caused by the pituitary.Advertisement
As of 2004, the best method to identify hGH-deficient patients was a positive stimulation test followed by a positive response to a therapeutic trial of hGH.
This procedure, also called the glucose loading test, is performed to evaluate excessive baseline levels of hGH and to confirm diagnosis of gigantism in children (and acromegaly in adults).
Normally, a glucose load such as this will suppress hGH secretion.
In a child with excessive hGH levels, failure of suppression indicates anterior pituitary dysfunction and confirms a diagnosis of gigantism (or acromegaly).
Other factors that may influence hGH secretion include stress, exercise, diet, and abnormal glucose levels.Advertisement
The hGH or somatotropin test requires that a fasting blood sample be drawn from a vein, usually in the arm.
Since stress and exercise increase hGH levels, the child must be at complete rest for 30 minutes before the blood sample is drawn.
Regarding growth hormone suppression, normally, glucose suppresses hGH to levels ranging from undetectable to 3 ng/ml within 30 minutes to two hours.
When caused by hGH deficiency, as opposed to late growth spurt or genetics, abnormally slow growth and short stature with normal proportions may be seen.
All healthy individuals have measurable levels of hGH throughout life, but there are two notable growth spurts, one at birth and the other at puberty, and hGH plays a vital role at each time.Advertisement
The most obvious effect of hGH is on linear skeletal growth (height), but metabolic effects of hGH (the results of hGH activity in the body) on muscle, the liver, and fat cells are a critical part of its function.