BASAL AND THYROTROPIN-STIMULATED SECRETION RATES OF THYROGLOBULIN FROM THE HUMAN THYROID-GLAND DURING SURGERY

The secretion rates of thyroglobulin were measured under basal conditi ons and after exogenous and endogenous thyrotropin stimulation in 23 p atients during surgery. In 11 patients with normal thyroid glands the median secretion rate of thyroglobulin was 0.7 pmol/24 h. Higher secre tion rates were observed in 8 patients with nontoxic nodular goiter (m edian 22 pmol/24 h; p < 0.001) and in 4 patients with thyroid malignan cy (median 2.2 pmol/24 h; p < 0.05). Within 10 min after administratio n of highly purified human thyrotropin into the thyroid artery an incr ease of the secretion rates was observed in the 9 patients studied wit h normal thyroid glands and 5 patients with nontoxic nodular goiter. T RH administration to 5 patients induced a slight but nonsignificant in crease of the secretion rate of thyroglobulin after 20 min. These resu lts show that thyroglobulin is secreted directly into the thyroid veno us blood. They also confirm that thyrotropin is an important regulator of the thyroglobulin secretion.