Fructose lowers cardiac copper in rats

A diet was made similar to that of Klevay containing finely ground zinc acetate and either fructose or corn starch. As the diet contained only 0.95 ..mu..g Cu/g, finely ground cupric sulfate was added to half of each carbohydrate diet so that 45 male, weanling Sprague Dawley rats could be fed in a 2x2 factorial design with normal or low Cu and fructose or starch to explore the lethal effect of fructose in Cu deficiency. Because analysis of diets by atomic absorption spectroscopy revealed a mean Zn of 14.8 ..mu..g/g and less Cu than expected (2.38 ..mu..g/g), normal Cu groups also received a drinking solution of 0.5 ..mu..g Cu/ml (as sulfate). Cholesterol was measured by fluorescence. Fructose lowered liver Cu (p = 0.0001) from 10.9 ..mu..g/dry g to 6.4 at normal dietary Cu and from 4.1 to 2.4 at low dietary Cu. Cardiac Cu, which was 16.9 and 8.7 ..mu..g/g respectively for starch and fructose groups at normal dietary Cu, was about 5.3 when dietary Cu was low (p = 0.0001). Plasma Cu was decreased 82 to 92% (p = 0.0001) by either fructose or low dietary Cu. Fructose lowered plasma cholesterol if dietary Cu was low or normal (pmore » = 0.006). Only rats fed low Cu and fructose were anemic (hematocrit 32, p = 0.0001). The harmful effect of fructose when dietary copper is low is not related to cholesterol metabolism but may be related to decreased cardiac copper.« less