Patients with chronic renal failure often have low plasma zinc (Zn) levels. Some factors that may account for abnormal Zn metabolism in these patients are low dietary Zn intake, a specific Zn transport defect, or absence of intestinal Zn ligand. In this study Zn supplementation and a Zn-chelating drug, diiodohydroxyquinolein (DQ), were used to assess the effects of Zn intake and Zn transporters on Zn plasma levels in patients with chronic renal failure. To meet this objective, 20 uremic patients were randomly assigned to one of the following groups of treatment: group 1 received placebo; group 2 Zn sulfate (100 mg/day p.o.), group 3 DQ (80 mg/day p.o.), and group 4 received Zn sulfate plus DQ at the same dosages as in groups 2 and 3. The Zn plasma levels were measured in venous samples, before and after 1 and 2 weeks of treatment, by atomic absorption spectrophotometry. The Zn plasma levels increased in group 2 patients from 8 +/- 0.2 to 10 +/- 0.4 and 11 +/- 0.9 mumol/l by the end of the 1st and 2nd weeks of treatment, respectively. In group 4 patients, the Zn plasma levels increased even more: from 9 +/- 0.1 to 14 +/- 1.6 and 13 +/- 2.1 mumol/l respectively. The plasma Zn concentration of group 1 and 3 patients remained at basal levels. These results show that DQ, when given along with Zn sulfate supplements, causes a greater increase in plasma Zn levels than that caused by either drug given alone.
