The effect of recombinant human TSH on 123I thyroid uptake after intravenous iodide contrast agent.

BACKGROUND: Recombinant human thyroid stimulating hormone (rhTSH) increases the thyroid radioactive iodine uptake (RAIU) in euthyroid and multinodular goiter patients. Furthermore, rhTSH is a well-known complementary tool in the management and treatment of differentiated thyroid cancer patients. OBJECTIVE: To evaluate the effect of rhTSH on RAIU in subjects without thyroid disease exposed to iodinated contrast agent during computed tomography (CT). METHODS: Nine euthyroid patients, seven female and two male, with ages ranging from 22 to 58 years, have signed a consent form approved by the hospital's Ethics Committee and had their TSH levels and RAIU evaluated in three moments: baseline (M1), 96 h after intravenous iodinated contrast agent (M2) and 24 h after intramuscular injection of 0.1 mg of rhTSH (M3). Each patient acted as his own control. RESULTS: There was significant variation throughout the study of TSH (mean+/-SD): M1=2.39+/-0.92 microUI/ml; M2=2.54+/-1.28 microUI/ml; M3=7.54+/-2.96 microUI/ml (P=0.004) and of RAIU (mean+/-SD): M1: 8.76+/-2.4%; M2=6.54+/-1.77%; M3=18.75+/-8.24% (P=0.002). In both cases, there was a significant increment from M1 and M2 to M3. CONCLUSION: It was shown that a single dose of 0.1 mg of rhTSH, given 96 h after the exposure to computed tomography iodinated contrast media, enhances the RAIU in nine euthyroid patients 4 h after 123I administration. These results indicate that rhTSH could be useful for avoiding delay in the treatment of patients with 131I.