Summary:
Chromium was known for many years to be an element causing allergic reactions and having neurotoxic and
carcinogenic effects. These effects can be observed especially in the case of hexavalent chromium. Only a little more
than four decades ago trivalent chromium has been known as an essential element with relation to glycide and lipid
metabolism. And only during several last years this chromium function has been revealed on a molecular level. After
absorption in the gastrointestinal tract, chromium is most likely transported to cells bound to the plasma protein
transferrin. Insulin initiates chromium transport into the cells where it is bound to the oligopeptide apochromodulin.
This oligopeptide combined with four chromium(III) atoms forms chromodulin, which is important for amplifying
the insulin signalling effect.After binding to insulin-activated receptor, chromodulin increases tyrosine kinase activity
by one order. This enzyme forms a part of intracellular portion of insulin receptor. Chromium supplementation in
people with chromium deficiency can improve glucose tolerance and some lipid metabolism parameters. The
supplementation is indicated in persons with impaired glucose tolerance both in praeclinical and manifested stadium
of type 2 diabetes mellitus where increased lost of chromium in urine was documented. In these patients, chromium
deficiency can participate in insulin resistance and hyperlipidaemia. Chromium is usually applied in the form of
organic compounds: yeast extract or chromium(III) picolinate. Cr(III) picolinate can be reduced to compounds of
Cr(II) in the cells which can then produce free hydroxyl radical in the so called Fenton reaction.
Key words:
chromium, chromodulin, diabetes mellitus, insulin, insulin resistance.
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