The chemical purity of the iodine in our Iodine is greater than or = 99.8%. We are more concerned about the purity than the actual source. Iodine from seaweed may possibly contain impurities found in the ocean such as arsenic, bromine in quantities that are not desirable or healthy.

Iodine Metabolism In the Thyroid

The major function of the gland is to concentrate iodine, and to synthesize thyroxine (T 4 ) or triiodothyronine (T 3 ). There is always about 20-50 mg of iodine in the body; 8 mg is in the thyroid. The supply may be variable. Iodine comes from water and food, but is also absorbed by intact skin and lungs. Throughout the world, the intake varies. 1 mg is needed per week, or about 50 mg/year. Diet under normal circumstances contains at least 150 micrograms daily.

The iodine pump (iodide trapping) gets the ion into the thyroid. It works against the concentration gradient which is at least 1 (blood) to 25 (gland). The pump is activated by pituitary TSH. ATP is utilized as a source of energy. Excess iodine in the gland inhibits the thyroid hormone synthesis.

Thyroid Hormone Synthesis

Iodide is first oxidized either into nascent iodine Io or I 3- The enzyme peroxidase is necessary as well as hydrogen peroxide. Then, iodine is attached to tyrosine which is the precursor of the thyroid hormones. Monoiodotyrosine and diiodotyrosine are formed by tyrosine iodinase.

Then, two molecules of iodinated tyrosine are coupled into T 3 and T 4 . T 3 is four times as potent as T 4 . About three quarters of the iodinated tyrosine never becomes thyroid hormones. They may be released from thyroglobulin and deiodinated by a deiodinase enzyme. About 90% of hormone produced is thyroxin. The hormones are formed within a globulin molecule in the thyroid and stored as thyroglobuline (MW about 670,000), where there are about 3 molecules of thyroxine and 1 molecule of T 3 per molecule of thyroglobulin. About 2 to 3 months of supply is stored in the gland.

Hormone release and transport

Thyroid hormone secretory pathway is composed of three steps:

* The internalization and intracellular transport of thyroglobulin,
* Proteolytic processing of the prohormone,
* Cellular handling and release of T 4 and T 3 .