The relationship of serum complement activity and bacteriostatic activity was investigated in male guinea pigs given aflatoxin and/or rubratoxin. In experiment 1, guinea pigs were given 0.6 mg of aflatoxin/kg of body weight, PO, once. In experiment 2, guinea pigs were given 0.02 mg of aflatoxin/kg, PO, and/or 8 mg of rubratoxin, PO, 11 times. Aflatoxin (0.02 mg/kg) had no effect given alone, but potentiated the effect of rubratoxin. In both experiments, changes in complement activity were accompanied by similar but not always significant (P less than 0.05) changes in bacteriostatic activity of serum. Guinea pigs given 0.06 mg of aflatoxin/kg had significant (P less than 0.05) changes in complement titers and in serum alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase activities. Guinea pigs given repeated oral doses of aflatoxin and/or rubratoxin had changes in complement titers, bacteriostasis, and alkaline phosphatase and aspartate aminotransferase activities, but not in alanine aminotransferase activities. Significant differences were detected only when average values for all guinea pigs given rubratoxin or rubratoxin with aflatoxin were compared with average values for guinea pigs not given rubratoxin.

The present study was carried out to investigate the effects of nitrate (KNO3) on the thyroid glands in rabbits which were administrated KNO3 of 1g/kg/day for 6 weeks. Growth rate, and serum levels for T4, T3 and TSH were observed every week. The histological changes and the weights of the thyroid glands were observed in 6 weeks. The mean growth rates of experiments were decreased significantly in the 1st week, but were increased a little from the 5th to 6th week compared with those of controls. The serum levels for T4 of the experimental group manifested significantly decreased values than those of control through the experimental term consistently and the serum levels for T3 were greatly decreased in the 3rd and 4th weeks. TSH contents of the serum were not changed through the experimental term. The mean weight of the thyroid gland in the experiment was decreased significantly after 6 weeks compared with that of cotrol. In the experimental group, the color of colloid in the thyroid follicles revealed deeper eosinophilic and the heights of the follicular epithelial cells were taller than those of controls. The colloid in the thyroid follicles revealed depletion. As summarized above, the observations suggest that nitrate can be an antithyroid substance in rabbits and it leads the thyroid glands to hypofunctional state