Immunofluorescent analysis of estrogen induction of progesterone receptor in the rhesus uterus.

Abstract

Estrogen (E) has been shown to induce an increase in progesterone (P) receptor (PR) concentration in uterine tissue of both rodents and primates. Because of the presence of different cell types within the uterus, we were interested in determining whether estrogen-induced PR were cell type specific in the nonhuman primate uterus (rhesus monkey). Immunofluorescent analyses of E receptor (ER) and PR were performed on fresh frozen cryostat sections (6 microns) of uterine tissue from ovariectomized (3 months) and estradiol (E2)-treated (peak level of E2 during an artificial menstrual cycle) rhesus monkeys. Antibodies to ER and PR were obtained from Abbott Laboratories (H222) and Transbio (MPR1). The avidin-biotin complex technique was used with streptavidin-conjugated Texas red for fluorescent detection. Ovariectomized monkeys showed positive fluorescence for ER in luminal and glandular epithelia, stromal cells, and smooth muscle cells of the myometrium. In contrast, positive fluorescence for PR was observed primarily in glandular epithelia, with little or no fluorescent detection in luminal epithelium, stromal cells, or myometrial smooth muscle cells. After E2 treatment strong positive fluorescence for PR was observed in luminal and glandular epithelia, stromal cells, and myometrial smooth muscle cells. Strong positive fluorescence for ER was also observed in the same cell types. Fluorescent detection of ER and PR was restricted to the nuclei of these cell types. These studies show that ER are present constitutively in all cell types of the E-withdrawn (ovariectomized) nonhuman primate uterus, whereas PR are primarily restricted to glandular epithelia. E2 treatment, which simulated the follicular phase and E2 surge, resulted in the appearance of immunofluorescent PR in luminal epithelia, stromal cells, and myometrial smooth muscle cells. These studies serve to define the cellular pattern of E2-induced PR in the primate uterus.