Insulin hypoglycemia excitatory growth hormone (GH) test
First, the principle and indications
Hypoglycemia stimulates glucose receptors in the brain, activates monoamine neurons to promote GHRH secretion through the α2 receptor, and inhibits the secretion of somatostatin. Therefore, the use of hypoglycemia can stimulate the physiological role of GH secretion, giving the subject a certain amount of insulin, causing hypoglycemia, measuring GH levels in different phases to observe the reserve function of pituitary GH, for GH deficiency diagnosis.
Second, the method
The subjects were fasted after midnight, and the saline was instilled intravenously before the morning to get the channel. Normal insulin 0.1 U/kg~0.15 U/kg body weight was added to 2 ml of normal saline for one intravenous injection. Obesity, Cushing syndrome or acromegaly is 0.2U/kg~0.3U/kg, and patients with suspected hypopituitarism can be used at 0.05U/kg body weight. Blood glucose measurement at the same time to measure blood glucose, blood glucose below 2.8mmol / L (some scholars require 2.2mmol / L) or more than 50% reduction before injection is effective stimulation. GH and blood glucose were measured before and 30, 60, 90, and 120 minutes after the test.
Third, the clinical significance and interpretation of the results
1. After using insulin in normal people, when the blood glucose drops to 2.2nmol/L or falls below 50% of the blood glucose before the insulin control, the GH should be significantly increased, and the peak value appears in 30 minutes-60 minutes, and the peak value can reach 15μg. /L ~ 30μg / L.
2, the normal child GH reaction positive rate is 74%-100%, there are a small number of false negatives, the general peak value is 15μg / L -30μg / L.
3, pituitary pygmy and anterior pituitary dysfunction, hygetropin HGH after reaction or low response with insulin, the general peak is more than 5.0μg / L.
4, hypercortisolism, hypothyroidism, hyperthyroidism, obesity and the use of large doses of glucocorticoids can reduce the response.
5, physical short stature, sexual developmental disorders (such as Turner syndrome, etc.), this experiment can be normal.
Fourth, matters needing attention
1. This test has certain risks, especially for children.
2. During the whole test, doctors should be closely observed. The hypoglycemia reaction is serious. If there are signs or symptoms of central nervous system, the test should be terminated, and 50% glucose 50ml~50ml, or oral glucose solution, and food should be given intravenously.
3, this test is banned in the elderly, heart, cerebrovascular disease and history of epilepsy.