Enhanced lipid peroxidation in liver microsomes of zinc-deficient rats

Abstract

The clinical association of decreased serum and hepatic zinc in patients with cirrhosis of the liver presumably arising from excess ethanol ingestion prompted a study of the activities of zinc and alcohol in experimental animals. The purpose of this study was to determine the effect of zinc deficiency upon lipid peroxidation in the liver. The effect of ethanol and zinc deficiency on lipid peroxidation was also evaluated. Rats were used in the experimental design, one group received a control diet, and one was maintained on a zinc-deficient diet. One-half of each group also received 3.85 g ethanol per kilogram body weight daily. Lipid peroxidation in vivo was determined by estimation of diene conjugation of microsomal lipids. The in vitro lipid peroxidation potential was measured by the generation of malonic dialdehyde by enzymatic as well as nonenzymatic reactions. Analysis of this data indicated that increased hepatic microsomal lipid peroxidation was associated with zinc deficiency whether using in vivo or in vitro indices of measurement. Review of the data from individual animals indicated that the lowest levels of serum zinc were associated with increased hepatic content of phospholipids. The degree of lipid peroxidation in the zinc deficient animals was not increased by ingestion of alcohol.

Effects of Zinc on Hepatic Antioxidant Systems and the mRNA Expression Levels Assayed by cDNA Microarrays in Rats

“…However, our results showed that GPx and GSH were unaffected by both zinc deficiency and zinc overdose, which was consistent with the findings of Buzadžić et al [32] who observed that Zn supplementation had no effect on liver GPx activity in contrast to the control group . In the present study, after subjecting the rats to a zinc deficiency the hepatic MDA and H 2 O 2 content increased, CuZn SOD as well as CAT activities were inhibited in comparison with the control group, which was mostly in agreement with the findings of other researchers [7,33] . However, Buzadžić et al [32] and Pathak et al [34] found that Zn supplementation had no effect on liver CAT activity.…”

“…The mechanism by which zinc deficiency induced lipid peroxidation could be explained on the basis of the following evidence. First, zinc deficiency was found to induce an increase in microsomal phospholipids with the resultant high level of unsaturated fatty acids vulnerable for lipid peroxidation [33] . Second, zinc deficiency was shown to increase NADPH and cytochrome P450-dependent production of carboncentered free radicals in rat liver microsomes [35] .…”

Nutrient-gene interactions: a single nutrient and hundreds of target genes

“…These functions become apparent during zinc deficiency, with markedly increased levels of lipid peroxidation in plasma membranes as well as in mitochondrial and microsomal membranes. This leads, for example, to an increased fragility of erythrocyte membranes and an impaired homeostasis of platelets (Sullivan et al, 1980;Bettger and O'Dell, 1981;Bray and Bettger, 1990;Oteiza et al, 1995).…”

Immune response in relation to zinc status, sex and antioxidant defence in Italian elderly population: the ZENITH study

“…A decline in immune function in elderly can also be the consequence of an accumulation of activated oxygen free radicals and decreased activity of antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) (Sullivan et al, 1980). Zinc plays an important role in the antioxidant defense system and zinc deficiency has been associated with increased reactive oxygen-induced damage in various tissues (Kraus et al, 1997).…”