Acute infusion of recombinant human thyrotropin in Langendorff-rat hearts: Role of a thyrotropin receptor

The bound of thyroid stimulating hormone (TSH) to its receptor elevates intracellular cAMP concentration that accounts for most of the biological actions of TSH. The presence and the patho-physiological role of a TSH receptor (TSHR) in heart is not yet clear. Understanding this question is important in the clinical use of recombinant human TSH (rhTSH) of patients with thyroid cancer. We investigate the acute effect of rhTSH in the Langendorff-perfused rat heart in relation with its receptor function. Compared to control group, no change in the hemodynamic parameters was observed in rat heart perfused with TSH. Western-blot of TSHR was performed evidencing the presence of the receptor and an increased level in cAMP was observed after thirty minute TSH perfusion. In conclusion the role of TSHR in rat heart seems to be marginal, reinforcing the idea of the cardiovascular safety of administered rhTSH in thyroid patients.