Trial Information

Study of Thyrotropin Releasing Hormone in Patients With Thyroid or Pituitary Abnormalities

Thyrotropin releasing hormone (TRH) is a neuropeptide used in the diagnostic evaluation of
patients with dysfunction of the hypothalamic-pituitary-thyroid (HPT) axis. In healthy
individuals, administration of TRH intravenously results in pituitary secretion of
thyrotropin [thyroid-stimulating hormone (TSH)], which in turn stimulates the thyroid gland
release of thyroid hormones; thyroxine (T4) and triiodothyronine (T3). TRH stimulates the
secretion of other pituitary hormones under normal physiologic as well as pathologic
conditions. The purpose of this study is to test the safety and activity of a new
preparation of TRH produced by the Pharmaceutical Development Section of the Clinical Center
Pharmacy at the NIH. This preparation is similar to a previously commercially available
preparation. Normal, healthy adults will be recruited to undergo a standard TRH test using
the new preparation. TSH, prolactin and thyroid hormones are measured after the
administration of TRH. After the safety, activity and diagnostic comparability are
established, the preparation will be used for routine diagnostic testing and research in
adults and children.