Dietary magnesium prevents fructose-induced insulin insensitivity in rats.

Abstract
Increased dietary fructose may produce insulin insensitivity and elevate blood pressure in rats. It is possible that the reduced magnesium content of the high-fructose commercial diet used in some studies may play a role in these abnormalities because it is known that magnesium deficiency can produce insulin insensitivity and increased angiotensin II action in humans. To study this, we maintained rats for 9 weeks on either a normal control diet, a standard high-fructose diet, or the same high-fructose diet supplemented with magnesium. Glucose uptake was assessed using a perfused rat hindquarter preparation sequentially with 0, 900, and 120,000 pmol/L of added insulin. Basal serum glucose, plasma insulin, and basal glucose uptake in the absence of insulin were similar among all three groups. However, insulin sensitivity, defined as glucose uptake in the presence of 900 pmol/L insulin minus basal, was depressed in the high-fructose compared with the control group (1.02 +/- 0.38 to 1.77 +/- 0.57 mumol/g per ...