title: Highly specific enzyme immunoassay for the beta-subunit of human thyrotropin with use of monoclonal antibodies.
abstract: A highly specific enzyme-linked "sandwich" immunoassay is described for determining free human thyrotropin (hTSH) beta-subunit in serum by using a anti-hTSH beta-subunit monoclonal antibody conjugated with beta-D-galactosidase (EC 3.2.1.23) and a solid phase consisting of silicone rods coated with another monoclonal antibody. We could detect as little as 0.04 ng of beta-subunit per assay. The measurable range of hTSH beta-subunit concentrations in serum was 0.4 to 50 micrograms/L. The assay demonstrated little or no cross reactivity with intact hTSH, hTSH alpha-subunit, or human choriogonadotropin. The mean CVs were 12.2% within assay, 13.9% between assay. The hTSH beta-subunit was not detectable in sera from healthy subjects, patients with hyperthyroidism, or two patients with pituitary tumors producing TSH. It was measurable (at concentrations of 0.65 to 2.70 micrograms/L) in sera from eight of 23 hypothyroid patients. In five of the hypothyroid patients examined, the concentration of hTSH beta-subunit in serum increased after administration of thyroliberin. This method may be useful in elucidating the physiological and pathological significance of the hTSH beta-subunit and in examining the function of the hypothalamus-pituitary-thyroid axis.
mesh_terms: D000293:Adolescent; D000328:Adult; D000911:Antibodies, Monoclonal; D002648:Child; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood; D007037:Hypothyroidism / Q000097:blood; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000097:blood; D011786:Quality Control; D013972:Thyrotropin / Q000097:blood*; D001616:beta-Galactosidase
chemical_list: D000911:Antibodies, Monoclonal; D013972:Thyrotropin; D001616:beta-Galactosidase