H. Vermeirsch et al., Immunohistochemical detection of progesterone receptors in the canine uterus and their relation to sex steroid hormone levels, THERIOGENOL, 53(3), 2000, pp. 773-788
The aim of this immunohistochemical study is to describe the normal distrib
ution of progesterone receptors in the various cell types of the canine ute
rine hems, body and cervix. The results can be used for research on uterine
and endocrinological pathology, since the impact of progesterone on differ
ent uterine cell types is partly determined by the receptor availability. N
uclear staining for progesterone receptors was observed in epithelial cells
of the surface epithelium, glandular ducts and basal glands of the endomet
rium, in endometrial stroma cells and in myometrial smooth muscle cells. Th
is staining was positively correlated with the estradiol-17 beta-progestero
ne ratio, and reflects the positive effect of estradiol-17 beta and the neg
ative influence of progesterone on the receptors. Staining scores were high
during proestrus and decreased through estrus to early metestrus. In late
metestrus, staining scores of the stromal and smooth muscle cells increased
again. In anestrus, high scores of the surface-epithelial cells contrasted
with minimal scores of the basal glands. This finding suggests a different
hormonal regulation of the progesterone receptor expression in both epithe
lial cell groups. The higher staining intensities for progesterone receptor
s in stromal cells compared with epithelial cells might be explained by the
fact that stromal cells mediate some effects of steroid hormones on the ep
ithelial cells in the genital tract. Therefore, the role of stromal cells i
n regulation of the cyclic endometrial changes and in pathologic changes of
uterine tissue should not be underestimated. (C) 2000 by Elsevier Science
Inc.