Abstract
The present study was undertaken to study the dose response of cadmium fluoride (CdF2) on indoleamine 2,3-dioxygenase (IDO) activity in the liver and kidneys of mice. The possible protective effect of quercetin on CdF2-induced alteration in enzyme activity was also studied. The following six groups, each consisting of six mice, were studied: (i) normal (control) group; (ii) mice treated with single i.p. injection of 1 mg/kg body weight (bw) CdF2; (iii) mice treated with single i.p. injection of 2 mg/kg bw CdF2; (iv) mice treated with single i.p. injection of 4 mg/ kg bw CdF2; (v) mice treated with single i.p. injection of quercetin (100mg/kg bw) alone; (vi) mice treated with i.p. injection of 100 mg/kg bw of quercetin followed by i.p. injection of CdF2 (2 mg/kg bw). Mice receiving 4 mg/kg bw of CdF2 died within 2 hours while those which received 2 mg/kg bw of CdF2 demonstrated a significant decrease in IDO activity in kidneys (p<0.001) and liver (p<0.01) compared to that of the control group. On the other hand, the 100 mg quercetin/kg bw injection resulted in a significant increase (p<0.001) in IDO activity in both organs when compared to control group of mice. Administration of quercetin 2 hours before injection of CdF2 resulted in resulted in the IDO activity in both liver and kidney remaining at near normal levels which were not significantly different from the control levels. In conclusion, CdF2 at different doses led to inhibition of IDO activity which may be due to stimulation of the nitric oxide synthase system.