The Effects of Oestrogen on the Cell Cycle in Epithelial and Connective Tissues of the Mouse Uterus

Abstract

The duration of stages of the cell cycle in the uterine epithelial and stromal tissues of ovariectomized mice was estimated by the labelled mitosis method. In untreated animals the mean duration of the S phase (DNA synthesis) was 10\m=.\5h in the glandular and luminal epithelium. Oestrogen treatment shortened it to 6 h in both tissues. In the endometrial stroma of progesterone\x=req-\ treated mice the duration of S was 8 h; when oestrogen was given it increased slightly. The generation times estimated under steady-state conditions were 270,156 and 383 h respectively in the lumen, glands and stroma of untreated mice. After oestrogen stimulation the responses became highly synchronized.

DNA Replication in Uterine Cells of Adult and Prepubertal Mice Under Normal and Hormonally Stimulated Conditions Detected by Bromodeoxyuridine Labeling Method.

“…Because the present study was aimed at following the previous findings on cell proliferation patterns in mouse uterine tissues under various conditions by using the BrdU labeling method as widely as possible, only one animal was used to survey the labeling incidences in each set of experimental conditions and therefore the results obtained were still insufficient for quantitative evaluation. From the qualitative aspect, however, the present results confirmed most of the previous findings obtained by autoradiographic studies on the hormonal regulation of uterine growth: the effect of E2 in increasing the DNA replication in epithelial cells (Epifanova, 1966: Galand et al, 1971: Martin et al, 1973a and that of P in suppressing the effect of E2 on the epithelia and promoting nucleic acid synthesis in stromal cells (Das, 1972: Martin et al, 1973b. The enhancement of DNA synthesis in all tissue components of the uterus by E2 in immature animals was the same as that reported in immature mice and rats (Kaye et al, 1972: Mukku et al, 1982: Quarmby and Korach, 1984, though Quarmby and Korach (1984) failed to induce myometrial hyperplasia by means of E2 treatment in mice.…”

Cell Division and Dna Synthesis in the Mouse Uterus During Continuous Oestrogen Treatment

“…One or two injections of oestrogen increase proliferation of uterine epithelial cells by shortening the generation time to between 11 and 26 h, mainly at the expense of the post-mitotic (Gx) phase (Epifanova, 1966;Das, 1972). On this basis cells should be capable of maintaining a high rate of cell division, but this does not happen after the 3rd day of oestrogen treatment, indicating that cells are either withdrawn from the proliferative compartment, or revert to a long Gv suggested that an apparent reduction in IL could be due to the shorter DNA-synthesizing (S) phase which followed oestrogen stimulation, so that a pulse of [3H]thymidine labels fewer cells.…”

Hypertrophy and Hyperplasia in the Mouse Uterus After Oestrogen Treatment: An Autoradiographic Study

“…The horizontal lines A1; Bj, C1( Dt show the cell numbers expected when all cells incorporating thymidine at times A, B, C and D respectively have divided. If the interval between mitosis (M) and the start of the period of DNA synthesis (S) lasts 1-5 h (Epifanova, 1966;Das 1972) As in Perrotta's (1962) experiment, increased thymidine incorporation preceded increased mitosis (Table 2; A and B) and there was no evidence for a subpopulation of cells in G2 which entered mitosis immediately on stimulation with oestrogen. In a group of five mice killed 21 h after 50 ng oestradiol and 6 h after [3H]thymidine, all epithelial mitoses were labelled.…”

“…Estimates of the duration of DNA synthesis in the oestrogen-stimulated uterine epithelia, vary greatly (Epifanova, 1966;Galand, Rodesch, Leroy & Chretien, 1967;Galand et al 1971 ;Das, 1972). The increases in luminal cell numbers during the first 15 h after oestrogen (Text- fig.…”