Two month glucocorticoid treatment increases estradiol-induced stromal and myometrial cell proliferation in the uterus of ovariectomized rats.

The present work was undertaken to examine the effect of 2 month glucocorticoid treatment on estradiol-induced proliferation in the uterus. Ovariectomized rats were treated with long-acting triamcinolone acetonide or saline for 60 days followed by a single injection of estradiol dipropionate or vehicle. Proliferation in the uterus was estimated by the mitotic index, bromodeoxyuridine-labelling index and proliferating cells nuclear antigen-labelling index 24, 36 and 48 h after the injection of estradiol or vehicle. Two month glucocorticoid treatment resulted in an initial decrease in all the parameters for luminal and glandular epithelia followed by an increase to 48 h after estradiol injection, and in a large increase in all proliferative parameters for stromal and myometrial cells at all periods of observation, compared with control rats untreated with glucocorticoid. The 2 month glucocorticoid treatment protocol had no significant effect on the parameters without estradiol administration. Analysis of proliferation for myometrial cells was also performed after 1 month treatment with glucocorticoid followed by estradiol or saline. Results showed no significant influence of 1 month treatment with glucocorticoid on myometrial cells.