Effects of oral ethinyl oestradiol and norethisterone on plasma copper and zinc complexes in post-menopausal women.

Orally administered ethinyl oestradiol increased the plasma total copper concentration and reduced the albumin concentration in post-menopausal women. Approximately 80% of the increase in copper was due to a rise in caeruloplasmin-bound copper and 20% to an increase in the amount of copper bound per gram of albumin. The plasma total zinc concentration was reduced, due partly to the decrease in albumin concentration and partly to a reduction in the amount of zinc bound per gram of albumin. Norethisterone had no significant effect on plasma copper but it reduced plasma zinc and albumin, though to a lesser extent than ethinyl oestradiol. When administered sequentially with ethinyl oestradiol, norethisterone diminished the effects of the former on plasma copper, zinc and albumin.

The effect of ethinyl oestradiol on calcium and bone metabolism in peri- and postmenopausal women.

The effects of ethinyl oestradiol on plasma and urinary calcium and other indices of bone turnover have been compared in peri- and postmenopausal women. In postmenopausal women ethinyl oestradiol caused significant decreases in the fasting plasma total and ionised calcium and phosphate concentrations, in alkaline phosphatase activity and in the fasting urinary Ca/Cr and OHPr/Cr ratios. Similar, but less marked, effects were observed in peri-menopausal women, with significant decreases in the fasting plasma phosphate and urinary Ca/Cr ratio. Small decreases in the plasma total and ionised calcium concentrations, in alkaline phosphatase activity and in the urinary OHPr/Cr ratio also occurred but were not statistically significant in our sample. Ethinyl oestradiol therefore appears to reduce bone loss in peri- as well as post-menopausal women, at least in the short term, but the effect is less pronounced in the former group.