Zj. Zhu et al., IODOTHYRONINE DEIODINASE ACTIVITY IN METHIONINE-DEFICIENT RATS FED SELENIUM-DEFICIENT OR SELENIUM-SUFFICIENT DIETS, Biological trace element research, 48(2), 1995, pp. 197-213
We examined the effect of methionine deficiency on iodothyronine 5'-de
iodinase activity in selenium-deficient rats or selenium-sufficient ra
ts fed sodium selenate or selenomethionine. Forty-two weanling male Wi
star rats were divided into six groups and pair fed the respective pur
ified L-amino acid-based diets for 4 wk. L-methionine concentrations i
n the-diet were 8.0 g/kg for sufficient rats, and 2.0 g/kg for deficie
nt rats. Selenium concentrations in the diet were 0.5 mg/kg (as sodium
selenate or selenomethionine) for selenium-sufficient rats and less t
han 0.005 mg/kg for selenium-deficient rats. Type I 5'-deiodinase acti
vities were significantly lower in liver and higher in kidney of methi
onine-deficient rats than in those of methionine-sufficient rats fed e
ither the selenium-sufficient or the selenium-deficient diets. The typ
e I 5'-deiodinase activity in brain was significantly lower in the met
hionine-deficient rats than in the methionine-sufficient rats fed the
selenium-deficient diet. Type II 5'-deiodinase activity in brain was s
ignificantly higher in the methionine-deficient rats than in the methi
onine-sufficient rats fed selenium-sufficient diet as sodium selenate.
Both thyroxine and 3,3',5-triiodothyronine concentrations in plasma w
ere significantly higher in the methionine-deficient rats than in the
methionine-sufficient rats. It is suggested that the methionine defici
ency affects the 5'-deiodinase activity and thyroid hormones level in
the rats.