Effect of vanadium, iodine and their interaction on growth, blood variables, liver trace elements and thyroid status indices in rats.

A two-factor, two-by-three factorially arranged experiment was performed to ascertain whether iodine affects the response of rats to vanadium deprivation. Male weanling Wistar-Kyoto rats were fed a 16% casein 68% acid-washed ground corn diet for 8 weeks. The variables were supplemental vanadium at 0 or 1 microgram/g and supplemental iodine at 0, 0.33 or 25 micrograms/g. Vanadium deprivation increased thyroid weight and thyroid weight/body weight ratio and decreased the concentration of vanadium in liver. Vanadium and iodine interacted such that, as dietary iodine was increased, plasma glucose increased in the vanadium-deficient rats but decreased in the vanadium-supplemented rats. Also, as dietary iodine was increased, thyroid peroxidase activity decreased; the decrease was more marked in the vanadium-supplemented than the vanadium-deprived rats. The findings suggest that vanadium may have a physiological role affecting iodine metabolism and thyroid function.