studies of the possibility that thyroxine ( t4 ) is converted to 3.5,3'-triiodo-l-thyronine ( t3 ) in the extrathyroidal tissues in man have been conducted in 13 patients , all but two of whom were athyreotic or hypothyroid , and all of whom were receiving at least physiological replacement doses of synthetic sodium-l-thyroxine.t3 was found in the sera of all patients , in concentrations ranging between 243 and 680 ng/100 ml ( normal range 170-270 ng/100 ml ) .
C0040165
thyroxine
C0020676
hypothyroid