Selenium derivatives of thyroxine and tri-iodothyronine

摘要

Novel Selenium derivatives of thyroxine and tri-iodothyronine have the formula: ##STR1## wherein M is I or H and either (a) R.sub.1 is OH or a carboxyl protecting group and R.sub.2 contains at least one Se, preferably .sup.75 Se, atom or (b) R.sub.2 is H or an amino protecting group and R. sub.1 contains at least one Se, preferably .sup.75 Se, atom. PP The compounds are useful in dual isotope assays of thyroid function.