Biological activity and fate of trace quantities of intravenous chromium (3) in the rat

Complexes of trivalent chromium were injected intravenously into rats raised on a low-chromium diet. Two hours after the injection of submicrogram amounts, impaired glucose removal rates were increased to near-normal values. The response of epididymal adipose tissue to insulin in vitro, as measured by the production of C14O2 from labeled glucose, was significantly enhanced in the chromium-injected animals. The amounts required for these effects were approximately 1/10,000 of doses producing acute toxicity. The whole-body disappearance of intravenously injected submicrogram amounts of chromium could be described by a multiexponential expression. Compartmental-type analysis revealed at least three regression rates. These rates were unaffected by previous dietary history with regard to chromium and were independent of absolute amounts injected. Intestinal absorption of chromium ranged around a few percent of the dose, regardless of amount applied, and was independent of dietary history.