Changes induced by cadmium administration on thyroxine deiodination and sulfhydryl groups in rat liver

The effects of cadmium on 5'-deiodination of thyroxine (T 4 ) by rat liver and on the hepatic concentration of non-protein sulfhydryl groups (NPSH) were studied in Wistar rats of 200-250 g body weight. A group of ten rats was injected with cadmium chloride (300 μg/100 g body weight i.p.) daily for 4 days. Another group of six rats received, in addition, dithiothreitol (DTT; 1 mg/100 g body weight i.p.) daily for the same period. A group of eight normal untreated rats served as control. T 4 deiodination was also determined in aliquots of liver from untreated rats, with cadmium (2 or 5 mmol/l) and with or without DTT (0, 2.5, 5 or 10 mmol/l) plus 1 μCi 125 I-labelled T 4