Magnesium Deficiency in the Rat Increases Tissue Levels of Docosahexaenoic Acid

Abstract

The effects of magnesium deficiency on tissue levels of total lipids and fatty acids were evaluated. Sprague-Dawley rats were fed a magnesium-deficient diet for 14 wk with controls being pair-fed to the deficient rats. Compared to the controls, serum and 24-h urinary magnesium levels were markedly lower in the magnesium-deficient rats. Serum cholesterol and total phospholipids were significantly higher in the magnesium-deficient rats than in the controls. Edema and polycystic degeneration of the kidneys were present in the magnesium-deficient rats. Kidney total phospholipids and triacylglycerols were significantly lower in the magnesium-deficient rats than in the controls. The main change in tissue fatty acid composition in magnesium deficiency was the higher docosahexaenoic acid (22:6n-3) in serum, liver and aorta than in controls. The possible relationship of these findings to human alcoholism is discussed.

Vitamin E Intake Affects Serum Thromboxane and Tissue Essential Fatty Acid Composition in the Rat

“…Phospholipids (PL) and triacylglycerols (TG) were separated by thin-layer chromatography and transmelhylatcd with boron trifluoride methanol. Fatty acid methyl esters were separated by gas-liquid chromatography as previously described [8]. PL were quantitated spectrophotometrically using the ammo- Table I.…”

Dietary fatty acid composition alters magnesium metabolism, distribution, and marginal deficiency response in rats*

“…In either case, the lack of a consistent significant effect of marginal magnesium deficiency on weight gain is consistent with depressed growth being found in some moderate magnesium deprivation studies but not in others. Marginal magnesium deficiency did not depress the weight of male rats whose dietary fat was palm oil [31], male rats whose dietary fat was groundnut/corn oil [32], male rats fed a high sucrose diet with soybean oil as the fat [21], or female rats fed a high sucrose diet with corn oil or soybean oil as the fat [33,34]. In contrast to females, male rats fed a moderately magnesium-deficient diet with corn oil for 4-6 months exhibited slightly depressed weight [23].…”

“…The change in membrane lipids apparently affected membrane fluidity. In contrast to the severe deficiency findings, more moderate magnesium deficiency (110 mg Mg/kg diet) of relatively long duration (14 weeks) increased the tissue levels of docosahexaenoic acid in rats [21]. In addition, the amount of eicosanoids (e.g., prostaglandin E 2 , thromboxanes, prostacyclin) from arachidonic acid was increased in plasma and tissues of rats fed about 73 mg Mg/kg diet for 12 weeks [22].…”

Overview of Magnesium Nutrition

“…The main change in tissue fatty acid composition in magnesium defi ciency was the higher docosahexaenoic acid in serum, liver, and aorta than in controls. 65 In the magnesium-defi cient rats, the percentage composition of triglycerides in very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) was elevated and that of protein was reduced. Although the proportion of cholesterol was reduced in LDL and HDL, that of phospholipid was decreased only in HDL.…”