EFFECT OF THYROID-STIMULATING HORMONE ON CULTURED THYROCYTES OBTAINEDFROM PATIENTS WITH GRAVES-DISEASE AND INHIBITIVE EFFECT BY SODIUM-IODIDE - A FUNCTIONAL-STUDY

Thyrocytes obtained from patients with Graves' disease were cultured f or 3 days, This was followed by culture with 10 mU/mL thyroid stimulat ing hormone (TSH) (ISH group), TSH and sodium iodide (Nal group), or w ithout (control group) for 3 additional days. On the 8th culture day, the amounts of intra- and extra-cellular cyclic adenosine monophosphat e (cAMP), extracellular cAMP and thyroglobulin (TG), peroxidase (PO) a ctivity, and cell numbers were measured, The amounts of intra- and ext ra-cellular cAMP correlated well, TSH increased the values of cAMP, TG and PO to levels higher than those of the control group, As the amoun t of Nal added to the medium increased, these values decreased. Additi on of 10(-5) mol/L Nal lowered the value of cAMP only, When 10(-4) mol /L Nal was added, these three levels were lower than those of the TSH group and the value of cAMP was almost equal to that of the control gr oup, On cell number, no difference was found between the cells culture d with TSH, TSH and Nal, and without TSH or Nal, When the thyrocytes w ere cultured with 1 mmol/L dibutyryl cAMP sodium salt or 8-bromoadenos ine 3', 5'-cyclic monophosphate instead of TSH, 10(-4) mol/L Nal did n ot lower the values of thyroglobulin and peroxidase activity, These re sults suggest that the Nal blocks the intracellular signal transductio n provoked by TSH, only at the cAMP production level.