The effect of intra-uterine contraceptive devices on the oestrogen-induced incorporation of [3H-5]uridine into RNA by the rat uterus.

A length of copper or stainless steel wire or of silk thread suture was inserted as an intra-uterine device (IUD) for 3 days in the right uterine horn of ovariectomized virgin female rats. The left horn served as a control. The control rats were ovariectomized but had no IUD inserted. The in vitro incorporation of [3H-5]uridine into uterine RNA was significantly inhibited (P less than 0.005) in copper-bearing horns compared to control horns, while silk and steel devices had no inhibitory effect, thus indicating an effect of intra-uterine copper on oestradiol-induced uterine metabolism. The insertion of an intra-uterine device had no significant effect on uterine wet weight, DNA content or on the uptake of [3H-5]uridine into the nucleotide pool.