Recombinant human thyrotropin stimulates thyroid function and radioactive iodine uptake in the rhesus monkey

The administration of bovine TSH to stimulate thyroid radioactive iodine uptake to detect functioning thyroid tissue in man after surgery for thyroid cancer is rarely, if ever, used, due to allergic reactions and/or the development of TSH antibodies. Human (h) TSH would be far less likely to induce allergic reactions or TSH antibodies. Recombinant hTSH (rec-hTSH) was produced by a line of Chinese hamster ovary cells that had been transfected with cDNA for the two subunit proteins that comprise hTSH. The present study was carried out to determine the half-life of rec-hTSH in the monkey and its ability to stimulate thyroid function. The half-life of rec-hTSH after iv administration was approximately 63 min for the rapid phase and 326 min for the slow phase. After three daily im injections of 2 U rec-hTSH to two monkeys, serum T4 concentrations increased several-fold, and serum T3 increased 2-3 times above basal values. The 6 and 20 h thyroid 123I uptakes doubled after rec-hTSH administration. These results demonstrate the biological efficacy of rec-hTSH administered to the monkey and strongly suggest that rec-hTSH will be effective in stimulating thyroid function in man.