Acute effects of recombinant human TSH on bone markers in differentiated thyroid cancer

Patients suffering from differentiated thyroid cancer receive suppressive of TSH thyroxine treatment of long duration. This study was undertaken to determine changes on bone serum markers after administration of recombinant human TSH in differentiated thyroid cancer patients on thyroxine treatment. Forty-five patients undergoing diagnostic evaluation of their disease and 48 matched controls were investigated: two injections of 0.9 mg of recombinant human TSH were given to the patients (on days 1 and 2). Blood samples were collected the day before first injection (day 0) and days 3, 5 and 10 after recombinant human TSH administration. Blood samples were obtained for serum TSH, bone alkaline phosphatase, osteocalcin, osteoprotegerin, receptor activator of nuclear factor kB ligand and bone tartrate resistant acid phosphatase. Recombinant human TSH induced a significant increase in bone alkaline phosphatase on day 3 up to day 10 in postmenopausal women. A statistically significant increase was also observed in serum receptor activator of nuclear factor kB ligand in both men and postmenopausal women on day 3 while on day 10 these values returned to baseline levels. No significant effects were seen in other parameters at any time of the investigation. In conclusion, we demonstrated significant increases in receptor activator of nuclear factor kB ligand and bone alkaline phosphatase after TSH stimulation. The changes in these bone indices were more prominent in the group of postmenopausal women.