DAILY MAGNESIUM SUPPLEMENTATION ON SERUM AND URINARY MAGNESIUM CHANGES IN RATS DURING PROLONGED RESTRICTION OF MOTOR-ACTIVITY

The objective of this investigation was to determine whether a plentif ul magnesium (Mg2+) supplementation might be used to normalize or prev ent Mg deficiency. This is manifested by increased rather than decreas ed serum Mg2+ concentration as is observed during prolonged hospitaliz ation, which is developed during prolonged hypokinesia (HK) (decreased motor activity). Eighty male Wistar rats with an initial body weight of 370-390 g were used to perform the studies: They were equally divid ed into four groups: 1. Unsupplemented control animals (UCA); 2. Suppl emented control animals (SCA); 3. Unsupplemented hypokinetic animals ( UHA); and 4. Supplemented hypokinetic animals (SHA). For the simulatio n of the hypokinetic effect, the hypokinetic animals were kept in smal l individual cages made of wood, which restricted their movements in a ll directions without hindering food and water intake. The control and hypokinetic supplemental animals receive 0.9 mg/mL Mg sulfate daily w ith their drinking water. Prior to and during the experimental period, urinary excretions of Mg, calcium, and phosphate along with their con centrations in serum, water intake, and urine excretion, and body weig ht were determined in the control and hypokinetic animals. In the supp lemental and unsupplemental hypokinetic rats, urinary excretions and s erum concentrations of electrolytes increased significantly, whereas s erum concentration and urinary excretion thereof remained unchanged in the supplemented and unsupplemented control animals. It was concluded that a daily intake of large amounts of Mg supplementation cannot be used to prevent or normalize Mg deficiency in rats during prolonged ex posure to HK.