Recombinant human thyroid stimulating hormone does not acutely change serum osteoprotegerin and soluble receptor activator of nuclear factor-κΒ ligand in patients under evaluation for differentiated thyroid carcinoma*

ObJEctIVE: some extra-thyroid actions of thyroid stimulating hormone (tsH), such as an in vitro action on bone, have been described. Our aim was to evaluate in vivo the acute effect of a recombinant human tsH (rhtsH)-induced tsH surge on Osteoprotegerin (OPG) and receptor activator of the nuclear factor-κb (rANK-L) levels in patients under levo-thyroxine (L-t4) therapy. DEsIGN: 24 patients with differentiated thyroid carcinoma (Dtc) were studied. standard rhtsH testing was performed. OPG, rANK-L, tsH, thyroid hormones, thyroglobulin and several parameters of bone metabolism were evaluated. rEsuLts: baseline OPG and rANK-L levels were in the range of our reference population. An inverse correlation between OPG and spinal Z-score (p=0.029) and between rANK-L and age (p=0.018) or urinary calcium/creatinine ratio (p=0.011) was detected. After rhtsH administration, a significant (p<0.001) increase in tsH was found. No significant increase in OPG or rANK-L levels after rhtsH was observed. No correlation was detected between tsH peak value after rhtsH and maximal percentage change in OPG or rANK-L. A slight increase in urinary cross-links after rhtsH was found. cONcLusIONs: In a small group of subjects with a history of Dtc on Lt4 regimen, our study did not support an acute direct effect of tsH on OPG and rANK-L.