ニバレノール(マイコトキシン)の代謝と毒性機構に関する研究 ： 第二報．ラットにおけるニバレノールの吸収，代謝，排泄および毒性について

Abstract

Absorption, distribution, and excretion of nivalenol and its major metabolite, deepoxynivalenol, were invesitigated in male rats after a single intraperitoneal (1 mg/Kg) or oral (5 mg/Kg) administration. After intraperitoneal administration, nivalenol and deepoxynivalenol excreted by the rats in urine were 48.3% and 3.8% of the total dose given respectively, and those excreted in feces were 10.0% and 25.5% of the dose, respectivly, within 72 hr. On the contrary, in oral administration, nivalenol and deepoxynivalenol excreted in urine were 9.9% and 5.6% of the dose, respectively, and those excreted in feces were 5.4% and 18.7% of the dose, respectively, in 72 hr. Deepoxynivalenol was excreted in feces to a higher extent than in urine and later than nivalenol. The levels of nivalenol detected in serum, liver and kidney were much lower than in urine or feces even 1 hr after oral dosing and were rapidly lowered. Deepoxynivalenol was not detected in serum, liver, or kidney at any time within 24 hr. The major metabolic pathways of nivalenol in rats are considered to be the deepoxidation at 12, 13-epoxide ring in the gastrointestine. The effect of feeding diets containing 0, 10, and 50 μg/g of nivalenol for 8 weeks on the growth rate, hematology, and histopathology were also examined. In 50 μg/g nivalenol dosing group, body-weight gain was significantly reduced and weak erythrocytopenia was observed. Histopathologically, mucosal necrosis and the disruption of gut epithelium, and an increase of erythroid series in bone marrow was observed. However, in 10 μg/g nivalenol dosing group, no significant change was observed in comparison with the control group.