Overview
Adrenal and gonadal (testes and ovaries) functions are assessed using dynamic testing in children and adults. Clinical decision-making is influenced by these tests in endocrine disorders, especially in those involving sex development and growth.
Diagnosis
Growth hormone (GH) stimulation test
In this test, the body is measured for its ability to produce growth hormone and to identify whether hGH (human growth hormone) deficiency is present. The test is performed by injecting one or two of various stimulants (glucagon, insulin, arginine, clonidine) into a vein or under the skin to raise hGH levels. Failure to see the expected rise suggests GH deficiency.
ACTH Stimulation Test
This is the most precise test for diagnosing adrenal insufficiency. Cortisol levels are measured before and after administering an injection of synthetic adrenocorticotrophic hormone (ACTH), a hormone produced by the anterior pituitary.
Water deprivation test
For several hours, you will be asked to stop drinking fluids while being monitored by a doctor/nurse and health care team. In order to prevent dehydration, vasopressin (an anti-diuretic hormone), stimulates your kidneys to decrease the amount of fluid lost through urine.
During this period, your doctor will measure body weight, urine output and urine concentration in the blood. Your doctor may also measure vasopressin levels in your blood or give you synthetic vasopressin. A test like this will determine if your body produces enough vasopressin and if your kidneys are able to respond as they should.
Insulin-Induced Hypoglycemia Test
The test involves taking blood samples and measuring blood glucose and cortisol levels, followed by injecting fast-acting insulin. After the insulin injection, blood glucose levels and cortisol levels are measured again 30, 45, and 90 minutes later. Blood glucose levels fall (this represents stress) and cortisol levels rise in response to stress. This test can assess the pituitary-adrenal axis to check for cortisol production and growth hormone sufficiency.
