Serum free thyrotropin subunit in congenital isolated thyrotropin deficiency.
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-alpha subunit (TSH-alpha) 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-alpha significantly increased following intravenous administration of thyrotropin releasing hormone (TRH). Serum free TSH-beta subunit (TSH-beta) 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-alpha, but to abnormalities of the TSH-beta gene.
Miyai
K
K
Department of Laboratory Medicine, Osaka University Medical School, Japan.
Endo
Y
Y
Iijima
Y
Y
Kabutomori
O
O
Hayashizaki
Y
Y
D000328:Adult; D003409:Congenital Hypothyroidism; D005260:Female; D015292:Glycoprotein Hormones, alpha Subunit / Q000097:blood* / Q000276:immunology; D006801:Humans; D007037:Hypothyroidism / Q000097:blood; D011863:Radioimmunoassay; D013972:Thyrotropin / Q000097:blood / Q000172:deficiency* / Q000235:genetics; D013973:Thyrotropin-Releasing Hormone / Q000008:administration & dosage
D015292:Glycoprotein Hormones, alpha Subunit; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin