ABSTRACT
Chromium has an interesting, albeit poorly understood, role in biology. Trivalent chromium is classified as a trace essential metal, but hexavalent chromium is classified as a human carcinogen. This chapter summarizes common in vitro techniques that have been applied to chromium nutritional research. Chromium is used in many industrial processes, including the production of stainless steel, the manufacture of dyes and pigments, and leather tanning. The glucose tolerance factor (GTF) was originally reported by Schwarz and Mertz to be a unique “dietary agent required to maintain normal glucose tolerance in the rat.” Several studies have used synthetic chromium complexes of glutathione and nicotinic acid as positive controls, but these compounds have not been structurally characterized, and no standard procedures exist for their synthesis. The GTF sample potentiated the effects of suboptimal insulin only in fat cells from rats fed the Torula yeast diet.
