Estradiol-type activity of coumestrol in mature and immature ovariectomized rat uterotrophic assays

Makaverich et al. [Environ Health Perspert 103:574-581 (1995)] reported tha t the uterotrophic activity of the phyoestrogen coumestrol in the immature ovariectomized rat was atypical in that it was not associated with increase d uterine hyperplasia and DNA content. We previously reported that coumestr ol gave a typical estradiol-type uterotrophic response in the immature inta ct rat, yielding increases in uterine epithelial cell height, glandular for mation, cell labeling, and DNA content. These papers did not answer the que stion of whether there is a basic difference between the ovariectomized and the intact rat uterotrophic assays. In this paper, we report that coumestr ol gives a typical estradiol-type uterotrophic response in uterotrophic ass ays using immature intact, immature ovariectomized, and mature ovariectomiz ed rats. We concluded that the uterotrophic activity of coumestrol is typic al of the natural estrogen estradiol.