[Effect of anti-thyroid antibodies on thyroid hormone secretion]

Secretory thyroid function was studied in animals with experimental autoimmune thyroiditis and in rats with passive immunization by antithyroid antibodies. The lowering of colloid endocytosis and thyroglobulin proteolysis accompanied by complete suppression of total thyroxin secretion stimulation was shown to occur in autoimmune thyroiditis. Injection to the rats of antibodies in the form of IgG gamma 2 fraction led to the reduced colloid output from the follicles, diminished secretion of triiodothyronine and to a pronounced suppression of thyroxin secretion stimulation. It is concluded that the lowering of colloid endocytosis and proteolytic enzymes is caused by insufficient production of TSH. Antithyroid antibodies should be treated as responsible for suppressed thyroxin secretion into the blood.