Effects of metal ions on plasma membrane Mg2+-atpase in rat uterus and ovaries.

The in vitro effects of cadmium and mercury were investigated on the Mg(2+)-ATPase activity of plasma membranes from the rat ovary and uterus. ATP hydrolyzing activities were significant and dose-dependent-inhibited in both plasma membrane preparations by both metals. According to the IC(50) and apparent K(i), Cd(2+) was most potent in the ovary, while Hg(2+) was most potent in the uterus. In ovaries and uterus, Cd(2+) inhibits competitively, while Hg(2+) inhibits noncompetitively in both organs. The observed inhibition was a consequence of direct action of the chosen metal ions on the enzyme protein and by decreasing ATP hydrolysis, Hg(2+) and Cd(2+) may affect mammalian fertility.