Involvement of prostaglandins in the effect of cupric ions on the human uterus

Abstract

The effect of cupric ions on the human uterus and the involvement of prostaglandins (PGs) in mediating this effect was studied by recording of isometric contractions of isolated myometrial strips and pieces of uterine arteries, and by intrauterine pressure recordings in women before the onset of menstruation. In vitro , CuCl 2 in concentrations of 10 −4 M and higher caused a significant inhibition of myometrial contractile activity, but no effect on the artery preparations was seen. Furthermore, the contractile response of myometrial strips to PGF 2α and PGE 2 (10 ng/ml) decreased in the presence of CuCl 2 in concentrations of 5 and 50 μmol. In vivo , instillations of 0.3, 1.0 and 2.0 mM of CuCl 2 in 0.7 ml of saline solution into the uterine cavity caused a dose-dependent stimulation of uterine activity, but after pretreatment with naproxen, 500 mg orally, the effect of these substances was abolished. After naproxen treatment, but during infusion of PGF 2α (5 μg/min), the response to the CuCl 2 solutions was partially restored. It is suggested that cupric ions, at high concentrations, have an inhibiting effect on myometrial activity. The stimulatory effect of low doses of CuCl 2 seen after installation into the uterine cavity is largely exerted via initiation of synthesis and release of endometrial PGs.