The Effect of a Copper IUD and “Inert” IUDS on the Incorporation of ³H‐Thymidine and 5‐³H‐Uridine Into the Endometrium of the Rabbit After Stimulation with Human Chorionic Gonadotropin

Abstract

The present investigation studied the influence of different types of intra-uterine devices (IUDs) especially that of a copper IUD, on the incorporation of 3-H-thymidine and 5-3-H-uridine into the endometrium of the rabbit. "Inert" IUD. In non-stimulated rabbits, the incorporation of 3-H-thymidine was increased in the copper influenced horn. The incorporation of 3H-thymidine in control and Cu-IUD-containing horns reached a maximum at 48 hours after HCG stimulation, but was significantly lower in the copper-containing horn than in the control horn. On the fifth day of pseudopregnancy, the incorporation of 3-H-thymidine was significantly higher in the copper IUD-containing horn. The total amount of DNA in the endometrium increased during early pseudopregnancy, but this increase was markedly reduced in the presence of copper. The copper IUD had no influence on the rate of incorporation of 5-3-H-uridine in non-stimulated rabbits, whereas it caused a higher incorporation on the fifth day of pseudopregnancy.

Effect of a Copper Iud on the Incorporation of [3h]thymidine and [5-3h]uridine Into the Endometrium of the Rabbit During Early Pregnancy

“…The effects of the Cu-IUD on the incorporation of [3H] thymidine into endo¬ metrial cells in pregnant rabbits agree well with those reported earlier in rabbits made pseudopregnant by stimulation with HCG (Grundsell & Häkansson, 1975), i.e. the incorporation of [3H]thymidine was depressed in the Cu-IUD-influenced endometrium at 60 hr p.c., whereas it was significantly increased in the Cu-IUD-containing horn at 120 hr p.c.…”

“…The endometrial proliferation following ovulation is the result of progesterone acting on oestrogen-primed endometrium (Allen, 1930;Hisaw & Leonard, 1930;Leonard, Hisaw & Fevold, 1932;Courrier, 1950;Leroy, 1974). A reduced endometrial proliferative response in the presence of a Cu-IUD, as demonstrated in the present study and in a previous study (Grundsell & Häkansson, 1975), may be due either to an altered hormonal responsiveness of the endometrium in the presence of copper or to a 'direct' effect of copper on nucleic acid metabolism.…”

“…Similar results have also been reported by Prager (1969) who found a decreased incorporation of [14C]thymidine into the endometrium of the rat in the presence of a copper IUD. It is possible, however, that Prager's results do not reflect an effect on DNA synthesis (Grundsell & Häkansson, 1975). The results in Table 4 show that the labelling frequency of epithelial cells influenced by copper was significantly lower than that of those influenced by a plastic IUD ; a slight tendency towards a lower labelling frequency of the stromal cells influenced by copper was observed.…”

“…Several reports on the effect of IUDs on the metabolism of nucleic acids have been published (for references, see Grundsell & Häkansson, 1975). Some of the results obtained are contradictory, e.g.…”

“…the discrepancy in the DNA content in the endometrium and in the endometrial cells (Hagenfeldt, 1972;Hagenfeldt & Johannisson, 1972) and the studies on the incorporation of labelled pre¬ cursors (Joshi, 1967;Laumas & Yadava, 1969). Grundsell & Häkansson (1975) studied the effect of a copper IUD and three 'inert' IUDs (two of plastic and one of platinum) on the nucleic acid metabolism in rabbits stimulated with HCG. The copper IUD inhibited the increase in DNA synthesis normally obtained 48 hr after stimulation, whereas the 'inert'…”