Hormone Testing

If you have a tumor involving the pituitary gland, we will order comprehensive hormone testing as part of your diagnosis. Our multidisciplinary team will evaluate and interpret the results. Sometimes, you may need specialized blood testing to diagnose your condition accurately. We have the sophisticated equipment necessary to obtain a diagnosis, even for complex cases.

Pituitary Function Testing

These are the hormones your doctor is evaluating during a hormone test:

• Prolactin. Normally, prolactin secretion by the pituitary gland stimulates a woman's breast to produce breast milk.
  • An excess may indicate a prolactinoma, a treatable pituitary condition. If the level is mildly elevated, it may be the result of a large pituitary adenoma or a side effect of certain medications.
  • A deficiency, together with a large pituitary tumor may be due to severe pituitary insufficiency of other hormones.
• IGF-1 (insulin-like growth factor-1, also called somatomedin C), is a hormone produced by special cells in the liver in response to growth hormone (GH) released by the pituitary. Both IGF-1 and GH are important for bone and muscle growth and maintenance.
  • An excess may indicate acromegaly, a condition almost always caused by a pituitary tumor secreting an excess of growth hormone.
  • A deficiency may indicate growth hormone deficiency, which is one type of pituitary insufficiency. In children, growth hormone deficiency results in stunted growth and other changes; in adults, growth hormone deficiency may be associated with loss of muscle mass and tone, as well as fatigue.
• Cortisol and ACTH. Cortisol is the "stress hormone" produced by the adrenal glands situated above the kidneys. Cortisol production is stimulated by the pituitary hormone ACTH (adrenocorticotropic hormone).
  • An excess of cortisol is called Cushing's syndrome; if the excess is due to a pituitary tumor secreting too much ACTH, it is called Cushing's disease. Diagnosing Cushing's disease requires highly specialized tests.
  • A deficiency of cortisol can be life threatening.
  • Your doctor will order a special test to assess if there is adequate cortisol in your system. We inject cortrosyn, or ACTH into your blood and check the cortisol level one hour later. The test is called the cortrosyn stimulation test.
• Thyroid function (fT4 and TSH). The thyroid hormone (free-T4 or fT4) and pituitary hormone TSH (thyroid stimulating hormone) are both measured.
  • Pituitary cells secrete TSH, which travels in the blood stream to stimulate thyroid cells (in the thyroid gland) to secrete thyroid hormone (T4) into the blood stream.
  • An excess of thyroid hormone (T4) is called hyperthyroidism.
  • A deficiency, or low thyroid function is called hypothyroidism. Large pituitary tumors can damage the normal pituitary gland, resulting in hypothyroidism.
• Testosterone and other sex hormones:
  • In males, measured to determine if there are sufficient quantities. Luteinizing hormone (LH) and follicle stimulating hormone (FSH) are pituitary sex hormones that are often tested in both males and females.
  • Low testosterone in males results in low sexual interest (low libido) and sometimes impotence. In females, gonadal failure can result in many symptoms, including infertility.

Contact Us

To schedule an appointment with one of our physicians at the Pituitary Tumor Program, please call (310) 825 5111.