Thyroid function and deiodinase activities in rats with marginal iodine deficiency.
The hypothesis tested was whether marginal iodine deficiency for a period of 6 wk affects iodothyronine deiodinase activities in liver and brain of rats. Male rats were fed purified diets either deficient or sufficient in iodine; the diets were fed on a restricted basis (60% of ad libitum intake). Body weight gain of the two groups was comparable. Iodine deficiency was evidenced by increased thyroid weight (26%), reduced urinary iodine excretion (80%), and reduced plasma T4 concentrations (22%). Activities of liver type I and brain type III deiodinase were unchanged, but the activity of type II deiodinase in brain was increased (28%) in the iodine-deficient rats. Food restriction per se significantly lowered T3 (30%) and T4 (22%) concentrations in plasma and decreased type III deiodinase activity in brain (30%). These results indicate that in marginal iodine deficiency the activities of hepatic type I deiodinase and brain type III deiodinase are unchanged, whereas that of brain type II deiodinase is increased.
Janssen
K P
KP
Department of Human and Animal Physiology, Agricultural University, Wageningen, The Netherlands.
Van Der Heide
D
D
Visser
T J
TJ
Kaptein
E
E
Beynen
A C
AC
D000818:Animals; D001921:Brain / Q000201:enzymology; D003404:Creatinine / Q000652:urine; D004032:Diet; D004435:Eating; D007453:Iodide Peroxidase / Q000378:metabolism*; D007455:Iodine / Q000172:deficiency*; D008099:Liver / Q000201:enzymology; D008297:Male; D009929:Organ Size / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013961:Thyroid Gland / Q000502:physiology*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D015430:Weight Gain / Q000502:physiology
D014284:Triiodothyronine; D007455:Iodine; D003404:Creatinine; D007453:Iodide Peroxidase; D013974:Thyroxine