The interaction between the TSH receptor and Graves' sera with TSH agonist or antagonist properties.
The A subunit of the TSH receptor was prepared by reduction of human thyroid membranes with dithiothreitol, and partially purified by gel filtration. The ability of Graves' sera to inhibit TSH binding to the TSH receptor and to stimulate cyclic AMP release from isolated thyroid cells was abolished by incubation with crude and partially purified preparations of the A subunit.