The thyroid prohormone thyroglubulin is a large soluble glycoprotein with a molecular weight of 660,000 daltons and a sedimentation coefficient of 19S. Thyroglobulin contains thyroxin rich iodopeptides of small molecular size(15,000 to
30,000).
Thyroglobulin is released from the thyroid under physiologic as well as pathologic conditions Serum thyroglobulin may show in creased levels in hyperthyroidism, thyroiditis, nontoxic goiter and thyroid carcinoma. Some investigators
have
reported the usefulness of serum thyroglobulin as a predictor of the long-term outcome of therapy after cessation of antithyroid drugs. Measurement of thyroglobulin and thyroid-stimulating immunoglobulin may become the ideal clinical index of
the
effect of antithyroid drugs in Graves' disease on the immunological basis. The author investigated serum thyroglobulin levels in patients with Graves' disease of 234 cases and Hashimoto's thyroiditis of 95 cases.
Serum thyroglobulin were 149.65±17.55ng/ml(M±SE) in Graves' disease, 51.09±13.66ng/ml(M±SE) in Hashimoto's thyroiditis and 8.25±1.36ng/ml in normal controls. In Graves's disease, serum thyroglobulin levels were well correlated with
radioactive iodine (I-131) thyroid uptake, serum T3 and goiter grades. Furthermore, the positive correlation between serum thyroglobulin levels and the parameters of hyperthyroidism became to be more escalated in the cases with a
negative
antithroglobulin antibody.
In Hashinoto's thyroiditis, serum levels of thyroglobulin had no significant correlations with thyroid function parameters, autoantibodies or goiter grades.
Therefore, serum thyroglobulin levels can be a useful mean of assessing the degree of thyroidal stimulation and correlated well with thyroidal stimulation especially in patients with a negative antithyroglobulin antibody.
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