Effect of fructose or starch on copper-67 absorption and excretion by the rat

Studies with 67Cu were conducted with copper-deficient or supplemented rats fed fructose or starch in an effort to investigate the effects of different dietary carbohydrates and inadequate copper intake on the absorption, tissue distribution and excretion of copper. After being fed their diets for 5 wk, they were killed at 8, 24, 48 and 96 h following the intubation of their respective copper-supplemented diets extrinsically labeled with 67Cu. Only at 48 and 96 h following the intubation of 67Cu, the gastrointestinal (GI) contents of rats fed the copper-deficient fructose diet exhibited higher radioactivity than rats fed the copper-deficient starch diet. Although not always significant, this apparent retention of copper in GI contents was accompanied by decreased whole-body radioactivity and depressed urinary excretion. The cumulative excretion of 67Cu via feces over the 96-h period of collection was similar for both groups of copper-deficient rats, regardless of whether the dietary carbohydrate was fructose or starch. The data suggest that the more severe copper deficiency is related to the sustained higher level of radioactivity in the GI contents. This increased retention of 67Cu in GI contents suggests impaired absorption of copper.