Impairment of iodothyronine 5'-deiodinase activity in brown adipose tissue and its acute stimulation by cold in selenium deficiency.
The activity of the type II iodothyronine 5'-deiodinase enzyme in brown adipose tissue has been examined in rats-fed a selenium-deficient diet. Iodothyronine 5'-deiodinase activity was threefold lower in brown adipose tissue of deficient rats than in control animals. The activity of glutathione peroxidase, a biochemical index of selenium deficiency, was also greatly decreased in deficient animals. Cytochrome oxidase activity in brown fat was, however, unaltered by selenium deficiency. Acute exposure to cold (4 degrees C for 18 h) resulted in a substantial increase in iodothyronine 5'-deiodinase activity in brown adipose tissue of control rats, but the stimulatory effect of cold was attenuated in selenium-deficient animals. These results support the concept that the iodothyronine 5'-deiodinases are selenium-dependent enzymes, and indicate that the thermogenic response to cold may be impaired in selenium deficiency.
Arthur
J R
JR
Division of Biochemical Sciences, Rowett Research Institute, Aberdeen, Scotland, U.K.
Nicol
F
F
Beckett
G J
GJ
Trayhurn
P
P
D000273:Adipose Tissue / Q000201:enzymology* / Q000254:growth & development; D000818:Animals; D001835:Body Weight / Q000502:physiology; D003080:Cold Temperature; D004032:Diet; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D007453:Iodide Peroxidase / Q000378:metabolism*; D008297:Male; D011506:Proteins / Q000378:metabolism; D051381:Rats; D012643:Selenium / Q000172:deficiency*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D011506:Proteins; D014284:Triiodothyronine; D007453:Iodide Peroxidase; D005979:Glutathione Peroxidase; D005978:Glutathione; D012643:Selenium; D013974:Thyroxine