Thyroid-Pituitary Interaction

Endocrinologists, particularly those with a special interest in thyroid disease, have been fortunate that several specific and sensitive tests that can establish the diagnosis of thyroid dysfunction have been developed over the past decade. The three most useful tests are radioimmunoassays of thyroxine (T4), 3,5,3′-triiodothyronine (T3), and thyrotropin, or thyroid-stimulating hormone (TSH).Clinicians have come to have so much confidence in the results of these tests that they often question their clinical acumen rather than the validity of a test when the two conflict. Diagnosis in thyroid disorders thus can be difficult not only because of the nonspecificity of symptoms, . . .