A radioautographic study of the inhibitory influence of repeated injections of estrone on cell division of the uterine epithelium of mice

Continuous oestrogen stimulation produced an initial increase in mitosis and [3H]thymidine incorporation in the mouse uterine luminal epithelium on days 2 and 3 of treatment, but activity fell to the level of the untreated uterus on days 4 and 5. The implications of this control of cell division are discussed. A second wave of activity occurred about a week later, and in the longest experiment a third wave was seen on days 19 to 21. This pattern was similar to that seen in the glandular epithelium. There was little cell division in the stroma or myometrium. The rhythm was not due to diurnal variation. It was seen after treatment with oestrone and oestradiol, given either by injection or in the drinking water.

Section: Discussioncontrasting

confidence: 49%

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

Lee¹

1972

“…Galand et al's (1967) 98 h continuous labelling experiment with oestrogen-treated animals shows evidence of this. Only 25 % of cells were labelled although the calculated generation time was 24-2 h. It appears that cells remaining in the proliferative compartment continue to show a shortened S phase (Epifanova «fe Smolenskaya, 1963). I am grateful to Dr L. Martin for his helpful criticism and continued interest during the course of this study.…”

Section: Resultsmentioning

confidence: 95%

“…An alternative explanation seems likely. Epifanova <fe Smolenskaya (1963) and Lee (1971) found that in mice treated repeatedly with oestrogen, the labelling and mitotic indices first rise and then fall as the epithelium becomes hyperplastic. This may involve a lengthening of G1 or the withdrawal of cells from the proliferative compartment.…”

Section: Resultsmentioning

confidence: 96%

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

Das¹

1972

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.

“…It seems evident that some cells were delayed in G2 and then divided at the same time as the 3H-labelled ones. Epifanova & Smolenskaya (1963) and Lee (1971) showed that in the uterine epithelium of ovariectomized mice given repeated injections of oestrogen when adult, the number of labelled nuclei and the mitotic rate increased at first but decreased eventually as the epithelium underwent hyperplasia. This phenomenon might be accounted for by a reduction in the probability of transition of cells from G1 into the replicative phase of the cell cycle (Das, 1972;Lee, Rogers & Trinder, 1974).…”

Section: Discussionmentioning

confidence: 97%

Effects of Postpubertal Oestrogen Injections on Mitotic Activity of Vaginal and Uterine Epithelial Cells in Mice Treated Neonatally With Oestrogen

Mori¹

1975

Cell cycles of vaginal and uterine epithelial cells were studies using [3H]thymidine autoradiography in adult ovariectomized mice given oestrogen injections neonatally. The mice were in a 'persistent-oestrous' state, showing ovary-independent, continued proliferation and cornification of the vaginal epithelium. The duration of different stages of the cell cycle could not be assessed in such mice, since the percentage of labelled mitoses failed to rise to 100%. In neonatally oestrogenized, adult mice the vaginal epithelium appeared to contain a mixed population of cells. After an oestrogen injection, almost all mitoses of vaginal epithelial cells became labelled, with a generation time of about 17 h. By contrast, the generation time was about 15 h in vaginal epithelial cells of ovariectomized 'normal' mice injected with oestrogen when adult. The uterine epithelium of neonatally oestrogenized, ovariectomized mice also consisted of a mixed population of cells. A single oestrogen injection produced an increase in both the mitotic rate and cell number in the vaginal and uterine epithelium of ovariectomized 'normal' adults but not in neonatally oestrogenized, ovariectomized adults. These studies show that in mice given oestrogen neonatally, uterine and vaginal epithelial cells were not responsive to oestrogen or at least less sensitive to oestrogen than ovariectomized 'normal' controls.