[Pre- and postoperative thyroglobulin secretion into the blood in nodular goiter]

Serum thyroglobulin was measured in patients with a euthyroid, preclinically hyperthyroid or toxic uni- or multinodular goiter (n = 72) prior to and/or 3-12 months following selective resection of the nodular goiter tissue. A sharp decrease in the mean and individually elevated serum thyroglobulin values was observed postoperatively, with normal or undetectable values in 92% of the patients. The pre- and postoperative thyroglobulin levels in multinodular goiter patients with hyperthyroidism, preclinical hyperthyroidism and euthyroidism were 102 +/- 79 micrograms/l vs. 10 +/- 7 micrograms/l; 77 +/- 62 micrograms/l vs. 16 +/- 22 micrograms/l; and 76 +/- 82 micrograms/1 vs. 18 +/- 26 micrograms/1 respectively. The pre- and postoperative values in uninodular goiter patients with TRH-TSH unresponsiveness and with a normal TSH response were 84 +/- 60 micrograms/l vs. 10 +/- 8 micrograms/l, and 105 +/- 115 micrograms/1 vs. less than 6 micrograms/1 respectively. Thus, the elevation of serum thyroglobulin proved to be unrelated to TRH-TSH responsiveness and to thyroid hormone secretion, but to be related to the presence of nodular goiter tissue. Follicular nodules lack normal TSH dependence with respect to goiter maintenance and growth. The results suggest that serum thyroglobulin may represent a marker of autonomous thyroid growth.