Advances in hormone testing made in 2001 have made accurate measurement of growth hormone (GH) levels possible. This is accomplished by measuring it directly in a 24-hour sample of urine. It is expected to replace IGF1 testing, which is an indirect measure of GH and less accurate. Direct GH testing is currently offered byAAL Reference Laboratories.
Low levels of IGF-1 are usually indicative of significant adult GH deficiency, but it is not a very sensitive test marker and will miss up to 60% of GH deficient patients aged over 40. Many endocrinologists will test to diagnose adult GH deficiencyby stimulating a GH response to a combination of GHRH and an inhibitor of somatostatin tone such as pyridostigmine, arginine, clonidine or insulin. Endocrinologists generally consider the insulin tolerance test (ITT) to be the most useful test to evaluate the overall GH secretion in subjects with possible hypopituitary disease . However, ITT is not suitable in elderly or in patients with cardiovascular disease or seizure disorders. Furthermore the GH response to ITT may be normal in “physiologic” GH deficiency, as it measures the overall capacity of the stress-axis rather than the physiological secretion of GH. A comparison of ITT, pyridostigmine plus GHRH (PD + GHRH) test, the clonidine plus GHRH (CLO+GHRH) test, and insulin-like growth factor I (IGF-I) in diagnosing GH deficiency has recently been reported. The peak GH response was significantly higher during the PD+GHRH test than during the ITT. IGF-I levels were subnormal in only 42% of the patients. It was recommended that adults with suspected GH deficiency and a normal IGF-I level should undergo two different stimulation tests. In patients with a subnormal IGF-I value, a single stimulation test would suffice to confirm the presence of GH deficiency.
Test Growth Hormone can help with the following
Key
| Highly recommended |
Glossary
Hormones
Chemical substances secreted by a variety of body organs that are carried by the bloodstream and usually influence cells some distance from the source of production. Hormones signal certain enzymes to perform their functions and, in this way, regulate such body functions as blood sugar levels, insulin levels, the menstrual cycle, and growth. These can be prescription, over-the-counter, synthetic or natural agents. Examples include adrenal hormones such as corticosteroids and aldosterone; glucagon, growth hormone, insulin, testosterone, estrogens, progestins, progesterone, DHEA, melatonin, and thyroid hormones such as thyroxine and calcitonin.
Arginine
A nonessential amino acid but may be essential for individuals with certain diseases or nutritional concerns. May promote the release of growth hormone. Involved in creatine synthesis, a compound that stores energy in muscle. Helps to remove ammonia from the body as part of the urea cycle.
Insulin
A hormone secreted by the pancreas in response to elevated blood glucose levels. Insulin stimulates the liver, muscles, and fat cells to remove glucose from the blood for use or storage.
Cardiovascular
Pertaining to the heart and blood vessels.
Seizure
While there are over 40 types of seizure, most are classed as either partial seizures which occur when the excessive electrical activity in the brain is limited to one area or generalized seizures which occur when the excessive electrical activity in the brain encompasses the entire organ. Although there is a wide range of signs, they mainly include such things as falling to the ground; muscle stiffening; jerking and twitching; loss of consciousness; an empty stare; rapid chewing/blinking/breathing. Usually lasting from between a couple of seconds and several minutes, recovery may be immediate or take up to several days.