Chromium has been known to be a micronutrient for mammals for four decades,
but progress in elucidating the role of chromium has proceeded slowly. How
ever, recent studies have shed light on a potential role of chromium in mai
ntaining proper carbohydrate and lipid metabolism at a molecular level. The
oligopeptide chromodulin binds chromic ions in response to an insulin-medi
ated chromic ion flux, and the metal-saturated oligopeptide can bind to an
insulin-stimulated insulin receptor, activating the receptor's tyrosine kin
ase activity. Thus, chromodulin appears to play a role in an autoamplificat
ion mechanism in insulin signaling. The molecular agent responsible for tra
nsporting chromium from mobile pools to insulin-sensitive cells is probably
the metal transport protein transferrin. Chromium from the popular dietary
supplement chromium picolinate enters cells via a different mechanism. Rel
ease of chromium from chromium picolinate for use in cells requires reducti
on of the chromic center, a process that can lead potentially to the produc
tion of harmful hydroxyl radicals.