抄録
In two patients with congenital isolated thyrotropin (TSH) deficiency, serum TSH determined by a sensitive immunoradiometric assay (IRMA) was consistently undetectable. The basal levels of serum free TSH-αsubunit (TSH-α) determined by a specific radioimmunoassay (RIA) were elevated in the hypothyroid state, and decreased to the undectable level during displacement therapy with thyroid hormone. The serum free TSH-αsignificantly increased following intravenous administration of thyrotropin releasing hormone (TRH). Serum free TSH-βsubunit (TSH-β) was undectable. These findings suggest that TSH deficiency in this disease is not due to absence of thyrotroph in the pituitary gland or deficiency of TSH-α, but to abnormalities of the TSH-βgene.
