tokens: Calling T3 100 , the order of potencies observed was : Triac , 500 ; 3 , 5-diiodo-3'-isopropylthyronine , 89 ; T4 , 32 ; 3 , 5-dimethyl-3'isopropylthyronine 2 ; 3 , 5-T2 , 0.7 , rT3 , 0.4 ; 3'5'-T2 , less than 0.01 .