Changes in cell proliferation rate in mouse uterine epithelium during continuous oestrogen treatment.

Abstract

SUMMARY Fraction of labelled mitoses (FLM) curves were constructed for mouse uterine luminal epithelium during oestradiol treatment; on day 2 when mitosis was high, and on days 4 and 9 when mitosis was low. No difference was found between the duration of DNA synthesis on these 3 days. The distance between the first and second peaks, usually taken as an estimate of the mean cell cycle time, did not change significantly between days 2 and 4, although the labelling index fell from 38 to 8%. The second peaks of the FLM curves became progressively lower on the three days examined, which was consistent with the interpretation that there was a reduction in the probability of transition of cells from G1 (the post-mitotic period) into the replicative phase of the cell cycle, resulting in the observed fall in mitotic index.