title: TSH binding by globulins from patients with Graves' disease.
abstract: Forty one globulin preparations from patients with Graves' disease were tested for their specific TSH binding properties and compared with their TSI activity in: 1. human thyroid membrane competition assay; 2. adenylate cyclase stimulation; 3. colloid droplet formation. The preparations tested were divided into two well distinguishable groups according to their specific TSH binding: 25 samples out of 41 contained thyrotropin binding sites similar to the globulins from normal healthy persons (A-type binding, Kd: 1.2 pmol-1 g and Bmax: 0.8 pmol g-1) and 17 samples bound TSH with lower affinity but higher capacity (B-type binding mean Kd: 15.3 pmol-1 g, mean Bmax: 2.7 pmol g-1). both A- and B-type TSH binding globulins containing samples were active in binding to human thyroid membrane, in droplet formation and adenylate cyclase stimulation. However, there was a linear correlation between the potential THS binding capacity of a B-type sample and the percentage adenylate cyclase stimulation and droplet formation, whereas the reverse correlation was found with their thyroid membrane binding activity. It was concluded that B-type TSH binding globulins may play a role in the formation and/or modification of the pathogenetic TSH action.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D013956:Antithyroid Agents; D001665:Binding Sites; D004789:Enzyme Activation; D006111:Graves Disease / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D018828:Immunoglobulins, Thyroid-Stimulating; D008135:Long-Acting Thyroid Stimulator / Q000037:antagonists & inhibitors / Q000378:metabolism; D008566:Membranes / Q000378:metabolism; D009930:Organic Chemicals; D013961:Thyroid Gland / Q000378:metabolism; D013972:Thyrotropin / Q000378:metabolism*
chemical_list: D013956:Antithyroid Agents; D007074:Immunoglobulin G; D018828:Immunoglobulins, Thyroid-Stimulating; D009930:Organic Chemicals; C018995:long-acting thyroid stimulator inhibitor; D013972:Thyrotropin; D008135:Long-Acting Thyroid Stimulator; D000262:Adenylyl Cyclases