Effect of magnesium deficiency on Δ6 desaturase activity and fatty acid composition of rat liver microsomes

Abstract

Experimental Mg2+ deficiency was induced in a group of rats by feeding them a Mg2+-deficient diet for 23 days. They were pair-fed to compare with a control group of rats fed a Mg2+-sufficient diet. In the Mg2+-deficient group the plasma total cholesterol and triglyceride levels were increased while HDL-cholesterol was decreased. In the Mg2+-deficient group the plasma level of thiobarbituric acid reacting substances (TBARS) used as a measure for lipid peroxidation was increased. The increase was attributed to the increased cytosolic Ca2+ in Mg2+-deficiency which can cause: 1) increase of hydro and endoperoxide levels as a consequence of the increase of arachidonic acid release and eicosanoid synthesis in Mg2+-deficiency, and 2) inhibition of the mitochondrial respiratory activity and activation of Ca2+-dependent proteases which may activate the conversion of xanthine dehydrogenase to xanthine oxidase which generates active O2 species. In the Mg2+-deficient group, the fatty acid composition of the liver microsomes indicated a slower rate of conversion of linoleic acid to arachidonic acid which was consistent with the decrease of delta 6 desaturase activity in liver microsomes of Mg2+-deficient rats as measured in vitro. The decrease of delta 6 desaturase activity was attributed to the lower concentration of actual enzyme molecules as a result of the decreased rate of protein synthesis in Mg2+-deficiency. The possible effects of the increased catecholamine release in Mg2+-deficiency are discussed.

Calcium deficiency modifies polyunsaturated fatty acid metabolism in growing rats

“…These early findings were then corroborated by other authors (15)(16)(17). Similarly, the effect of magnesium as an essential cofactor in the fatty acid oxidative desaturation reactions was previously reported (1,18). Τhe ∆5 and ∆9 desaturation steps are also particularly influenced by the level of copper, which has an opposite effect to that of zinc (19)(20)(21)(22)(23)(24)(25)(26).…”

Mg supplementation attenuates ritonavir-induced hyperlipidemia, oxidative stress, and cardiac dysfunction in rats

“…We, as well as others (5,29, 41), have reported that Mg deficiency may promote hyperlipidemia. Moreover, an earlier study indicated that Mg supplementation could attenuate diet-induced triglyceridemia in a rabbit model (3).…”

“…Mg may play a key role in the regulation of carbohydrate and lipid metabolism (44,45). Severe magnesium deficiency can promote lipogenesis (5,29,41). In the present study, RTV treatment alone decreased circulating Mg levels, but this decrease was mild (Ϫ12%) and may not be the major cause leading to hyperlipidemia.…”

Higher Levels of Magnesium and Lower Levels of Calcium in Whole Blood Are Positively Correlated with the Metabolic Syndrome in a Chinese Population: A Case-Control Study

“…Analysis of cross-sectional data obtained from 123 subjects in Korea indicated that there was no significant difference in Mg concentrations between the MetS group and the control group [45] . Deficiency in blood concentrations of Mg has been reported to affect the activities of enzymes and cause metabolic disorders [46][47][48] . However, in this study, we observed opposite correlations between Mg and BMI, blood pressure, blood lipid and blood glucose levels.…”