Long-Term Dietary Iodine Deficiency Alters Transport of 2-Deoxy-D-Glucose across the Adult Rat Blood-Brain-Barrier

Iodine deficiency affects all stages of life, and impaired mental function is five times as common as cretinism among populations living in iodine-deficient areas. The possibility that this could be due to an altered nutrient supply to the brain has been tested in albino rats chronically fed an iodine-deficient diet. Transport of [14C]-labelled nutrients across the blood-brain barrier (BBB) was determined in situ by the brain uptake-index (BUI) method. Feeding a low-iodine test diet (LIT) (0.0228μgI/g) to weanling Wistar/NIN rats for a short term (8 weeks) had only a modest effect on their tyroid status and no effect at all on their body or brain weight or their BBB transport of 2-deoxy-D-glucose (2-DG) as compared to control rats fed either the LIT diet+KI(-3μg I/g diet) or a locally formulated control diet of similar composition (-3μgI/g diet). On the other hand, long-term (16 weeks) dietary iodine deficiency in four different strains of rats produced a moderate hypothyroidism and significantly (p