Iodothyronine deiodinase activity in methionine-deficient rats fed selenium-deficient or selenium-sufficient diets.
We examined the effect of methionine deficiency on iodothyronine 5'-deiodinase activity in selenium-deficient rats or selenium-sufficient rats fed sodium selenate or selenomethionine. Forty-two weanling male Wistar rats were divided into six groups and pair fed the respective purified L-amino acid-based diets for 4 wk. L-methionine concentrations in the diet were 8.0 g/kg for sufficient rats, and 2.0 g/kg for deficient rats. Selenium concentrations in the diet were 0.5 mg/kg (as sodium selenate or selenomethionine) for selenium-sufficient rats and less than 0.005 mg/kg for selenium-deficient rats. Type I 5'-deiodinase activities were significantly lower in liver and higher in kidney of methionine-deficient rats than in those of methionine-sufficient rats fed either the selenium-sufficient or the selenium-deficient diets. The type I 5'-deiodinase activity in brain was significantly lower in the methionine-deficient rats than in the methionine-sufficient rats fed the selenium-deficient diet. Type II 5'-deiodinase activity in brain was significantly higher in the methionine-deficient rats than in the methionine-sufficient rats fed selenium-sufficient diet as sodium selenate. Both thyroxine and 3,3',5-triiodothyronine concentrations in plasma were significantly higher in the methionine-deficient rats than in the methionine-sufficient rats. It is suggested that the methionine deficiency affects the 5'-deiodinase activity and thyroid hormones level in the rats.
Zhu
Z
Z
Department of Hygiene, Faculty of Medicine, Kyoto University, Japan.
Kimura
M
M
Itokawa
Y
Y
D000818:Animals; D001835:Body Weight / Q000502:physiology; D004032:Diet; D004229:Dithiothreitol / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D007202:Indicators and Reagents; D007453:Iodide Peroxidase / Q000378:metabolism*; D008297:Male; D008715:Methionine / Q000172:deficiency*; D009929:Organ Size / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012643:Selenium / Q000008:administration & dosage / Q000172:deficiency* / Q000378:metabolism; D012645:Selenomethionine / Q000378:metabolism*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D007202:Indicators and Reagents; D014284:Triiodothyronine; D012645:Selenomethionine; D008715:Methionine; D007453:Iodide Peroxidase; D005979:Glutathione Peroxidase; D005978:Glutathione; D012643:Selenium; D013974:Thyroxine; D004229:Dithiothreitol