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Pituitary Disorders

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Laboratory testing may be used to detect excess or deficient hormones, help diagnose a pituitary disorder, determine the severity, and may be ordered at intervals to monitor the effectiveness of treatment over time. Some individuals may have inherited conditions and thus a lifetime risk of developing a pituitary disorder, so long-term monitoring may be necessary in some cases.

Testing frequently includes measurements of both the hormones that the pituitary produces, such as thyroid-stimulating hormone (TSH), and the hormones of other endocrine glands that the pituitary stimulates, such as the thyroid gland hormone T4 (thyroxine).

Examples of hormones that may be tested in the evaluation of pituitary disorders include:

Pituitary hormones are released as needed so levels in the blood may:

  • Be relatively constant (e.g., TSH)
  • Vary over the course of a day (e.g., cortisol)
  • Vary over a cycle (e.g., FSH and LH during the menstrual cycle)
  • Be increased in specific situations, such as prolactin in women who are breastfeeding or ACTH as a response to stress

Because of these variations in when hormones are released, detecting excess and deficient hormones often requires tests that measure hormonal changes after a person takes medications to suppress or stimulate the production of hormones (i.e., suppression or stimulation tests).

A water deprivation test, which involves measuring urine and serum osmolality, may be used to help diagnose diabetes insipidus.

Imaging tests may be used to evaluate glands and detect tumors. These may include:

  • MRI (magnetic resonance imaging)
  • CT (computed tomography)

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