Chromium-induced glucose uptake, superoxide anion production, and phagocytosis in cultured pulmonary alveolar macrophages of weanling pigs

The dose-dependent effects of chromium chloride(CrCl3) and chromium picolin ate (CrPic) were evaluated for their glucose uptake, superoxide anion (O-2( -)) production, activity of glucose-6-phosphate dehydrogenase, and phagocyt osis of incubated pulmonary alveolar macrophages in medium containing no or 5 x 10(-8)M insulin. Glucose uptake was found to increase in cells treated with 20 mug/L CrCl3. Incubation with 20 mug/L of CrPic enhanced glucose up take and O-2(-) production in an insulin-dependent manner. However, the inc lusion of CrPic to 100 mug/L in the medium absent of insulin also increased O-2(-) production. The activity of glucose-6-phosphate dehydrogenase was n ot affected by either the addition of Cr or insulin. The phagocytosis of Es cherichia coli by macrophages was enhanced significantly (p < 0.05) in medi um containing 10-100 <mu>g/L CrCl3 or 20-100 mug/L CrPic in the presence of insulin. These results suggest that the addition of 10-20 mug/L CrCl3 enha nces directly the cellular activity of macrophages, whereas the effect of C rPic requires the cooperative action of insulin in enhancing their glucose uptake and phagocytosis.