Lipid alterations in the liver and serum of rats in histidine-excess and copper deficiency

To obtain further information on lipid metabolism in the histidine-excess and copper-deficiency, rats were fed basal, histidine-excess (the addition of 50 g L-histidine/kg diet) or copper-deficient diets for 0, 7, 21 and 42 d ad libitum. Liver triacylglycerol accumulated and the serum triacylglycerol level decreased after feeding of the histidine-excess diet for 21 or 42 d, but not after feeding of the copper-deficient diet. Serum cholesterol level increased in rats fed the histidine-excess diet for 7, 21 and 42 d, but not in rats fed the copper-deficient diet. Copper content in the liver and serum significantly decreased in rats fed the histidine-excess diet. Copper content in the liver and serum was markedly decreased in rats fed the copper-deficient diet. Liver zinc content was constant, but the serum zinc level decreased in rats fed the histidine-excess diet. Feeding of the copper-deficient diet hardly affected zinc content in the liver and serum. Urinary copper and zinc increased in rats fed the histidine-excess diet, and decreased or showed a decreasing tendency in rats fed the copper-deficient diet. Overall results indicated that feeding the histidine-excess diet caused copper deficiency, whereas hypercholesterolemia was not shown in rats fed the copper-deficient diet although the livers of rats fed the copper-deficient diet contained less copper than those of rats fed the histidine-excess diet. Thus, the responses on liver triacylglycerol and serum cholesterol to copper deficiency induced by the feeding of a histidine-excess diet are different from those to copper deficiency induced by feeding of a copper-deficient diet.