Effects were related to age at first exposure. Uterotropic effects of EV were confined largely to the endometrium on PND 7 and 14 and, overall, were greater in older animals . Age-specific responses of neonatal porcine uterine tissues were interpreted to suggest that acquisition of estrogen sensitivity occurs progressively in the developing uterine wall and that estrogen-sensitive uterine cell populations develop first in the endometrium. buy ortho tri-cyclen
Ontogeny of ER expression in the neonatal porcine endometrium has not been characterized, nor is it known whether ovarian factors affect patterns of endometrial ER expression during the period between birth and PND 120 as the porcine endometrium is becoming structurally and functionally mature. Moreover, delineation of mechanisms through which estrogens or related xenobiotics may affect normal uterine growth and development, or induce developmental lesions in these tissues, requires that ER-positive cell populations be identified and that patterns of development of ER-positive cell populations be characterized in situ. Therefore, objectives of die present study were to determine effects of age and of ovariectomy at birth on patterns of uterine growth, endometrial development, distribution of ER-positive endometrial cells, and endometrial ER gene expression in situ between PND 0 and 120 in the porcine uterus.