Urinary magnesium in early postmenopausal women: influence of hormone therapy on calcium

The urinary excretion of magnesium was studied in two groups of healthy women just after menopause. The women in group I were randomly allocated to receive either placebo or 4, 2 or 1 mg 17 beta-oestradiol in cyclical combination with 1 mg norethisterone acetate (a progestational agent). Oestradiol was given, in the above-mentioned doses, from days 1 to 22, and 1, 1 or 0 mg oestradiol was given from days 23 to 28, in combination with norethisterone acetate from days 13 to 22 and oestriol 2, 1 or 0.5 mg from days 1 to 23 and 0.5, 0.5 or 0 mg from days 23 to 28. The women in group II were allocated to receive either placebo, 2 mg oestradiol valerate in cyclical combination with 1 mg cyproterone acetate (oestradiol valerate from days 1 to 21 and cyproterone acetate from days 12 to 21) with 1,000 mg of calcium per day or oestradiol valerate + cyproterone acetate without calcium. Oestrogen and progesterone therapy decreased the urinary magnesium excretion significantly when compared to the placebo group. The effect was related to the dose of oestrogen. Furthermore, our results indicate that calcium supplementation influences the urinary excretion of magnesium in a two-phase paradoxical manner.