Formation and Metabolism of 3',5'-Diiodothyronine and 3,5-Diiodothyronine by Cultured Monkey Hepatocarcinoma Cells

Abstract

Cultured monkey hepatocarcinoma cells were incubated with |3',5'-¹²⁵I]diiodo-L-thyronine and with [3,5-¹²⁵I]diiodo-L-thyronine. In both instances monodeiodination as well as sulfoconjugation took place. [3.-¹²⁵I]iodothyronine and [3',5'^-125I] diiodothyronine were identified as metabolites of [3'-5',-¹²⁵I]-L-thyroxine in the cells, but neither [3-¹²⁵I]-iodothyronine nor [3,5-¹²⁵I] diiodothyronine was detected after incubation of the cells with [3,5-¹²⁵I]-L-thyroxine. No products of diphenyl ether splitting were observed in the medium after incubation of the cells with either [3,5-¹²⁵I] diiodo-L-thyronine or [3,5-¹²⁵l]-L-thyroxine.