Kinetics of copper absorption in zinc-overload states and following the withdrawal of zinc supplement: the role of endogenous zinc status.
Zinc (Zn), in therapeutic dosages, has been used to inhibit copper (Cu) absorption in patients with Wilson's disease. A series of experiments were conducted to substantiate the effects of high dosages of Zn on Cu absorption using the experimental animal model. In the first experiment, five groups of mice were fed five different levels of Zn: 6 ppm (basal diet), 30 ppm (control), 750 ppm, 1,000 ppm, and 2,400 ppm, for a period of 35 days. 64Cu-loading test was conducted to measure whole body retention (WBR) of 64Cu at the 10th, 14th, 21st, and 35th day. Results showed that the inhibition of 64Cu absorption by Zn is dose- and time-dependent. However, maximum inhibition occurred in mice fed 1,000 ppm of Zn, and no additional effect was observed in mice fed 2,400 ppm of Zn. In the second experiment, the distribution between the gastrointestinal tract (GIT) and gut-free carcass, of the retained dose of 64Cu, was measured in controls and in the group fed 750 ppm of Zn. While WBR of 64Cu was significantly lower (p less than 0.01) in mice fed 750 ppm of Zn, the distribution of the retained dose was not affected. In the third experiment, a group of mice was fed 30 ppm of Zn for a period of 70 days (control), and a second group was fed 1,000 ppm of Zn for the first 35 days (repletion), after which they were switched to the basal diet (6 ppm) for the following 35 days (depletion). WBR of 64Cu was conducted in intervals throughout the experimental period.(ABSTRACT TRUNCATED AT 250 WORDS)
Cossack
Z T
ZT
Division of Nuclear Biotechnique, Interuniversity Reactor Institute, Delft, The Netherlands.
van den Hamer
C J
CJ
D000818:Animals; D003300:Copper / Q000493:pharmacokinetics*; D005527:Food, Fortified; D006527:Hepatolenticular Degeneration / Q000188:drug therapy / Q000378:metabolism; D007408:Intestinal Absorption / Q000187:drug effects*; D008657:Metabolic Clearance Rate; D051379:Mice; D008815:Mice, Inbred Strains; D015032:Zinc / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*
D003300:Copper; D015032:Zinc