Interaction between nickel and iron in the rat.

The interaction between nickel and iron was confirmed in rat metabolism. In a fully-crossed, two-way, three by four, factorially designed experiment, female weanling rats were fed a basal diet supplemented with iron at 0, 25, 50, and 100 µg/g and with nickel at 0, 5, and 50 µg/g. The basal diet contained about 10 ng of nickel and 2.3 µg of iron/g. After nine weeks, dietary iron affected growth, hematocrit, hemoglobin, plasma cholesterol, and in liver affected total lipids, phospholipids, and the contents of copper, iron, manganese, and zinc. By manipulating the iron content of the diet, effects of dietary nickel were shown in rats that were not from dams fed a nickel-deprived diet. Nickel affected growth, hematocrit, hemoglobin, plasma alkaline phosphatase activity, plasma total lipids, and in liver affected total lipids, and the contents of copper, manganese, and nickel. The interaction between nickel and iron affected hematocrit, hemoglobin, plasma alkaline phosphatase activity, and plasma phospholipids, and in liver affected size, content of copper, and perhaps of manganese and nickel. In severely iron-deficient rats, the high level of dietary nickel partially alleviated the drastic depression of hematocrit and hemoglobin, and the elevation of copper in liver. Simultaneously, high dietary nickel did not increase the iron level in liver and was detrimental to growth and appearance of severely iron-deficient rats. In nickel-deprived rats fed the borderline iron-deficient diet (25 µg/g) hematocrit and hemoglobin also were depressed. However, 5 µg Ni/g of diet were just as effective as 50 µg Ni/g of diet in preventing those signs of nickel deprivation. The findings in the present study suggested that nickel and iron interact with each other at more than one locus.