| Research Abstract |
Permanent effects of hormones on accessory organs and apoptosis of reproductive tracts were studies.
1. Oncogene expression. (1) In ovariectomized adult mice, a single injection of estrogen induced expression of oncogenes (fos, jun), however, permanent expressions of fos and jun were encountered in permanently changed vagina in neonatally DES-exposed mice.
2. Steroid receptor expression. (1) Neonatally DES exposure significantly lowered EGF receptor levels and estrogen receptor (EG) mRNA levels in vagina. (2) ER in uterine epithelial cells began to appear by day 5, however, DES induced it 12 h after the injection in uterine epithelial cells. (3) ER was not expressed in reproductive tracts of newborn male mice except for ductus efferens. Neonatal DES exposure induced ER expression in male genital tracts. (3) Progesteorne receptor was demonstrated in rat uterus by immunohistochemistry.
3. Apoptosis of vagina and pregnancy-dependent mammary tumor (PDMT). (1) DNA fragmentation was induced in vagina, but not uterus, by ovariectomy. Ovariectomy induced expression of TNF-alpha but lowered expression of bcl-2 gene. Fas expression was not altered by ovariectomy. (2) DNA fragmentation was encountered in PDMT just after the parturition.
4. Growth of placental cells in vitro. (1) Estradiol, progesterone and a combination of these steroids stimulated proliferation of the trophoblastic cells only from the 6th and the 10th days. Keoxifene, but not tamoxifene, inhibited the estrogen-induced proliferation of trophoblastic cells. EGF and TGF- stimulated the proliferation of trophoblastic cells from the 6th and the 10th days but not from the 14th and the 18th day.
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