Diethylstilbestrol increases the density of prolactin cells in male mouse pituitary by inducing proliferation of prolactin cells and transdifferentiation of gonadotropic cells.
ABSTRACT Diethylstilbestrol (DES) has been implicated in mammalian abnormalities. We examined the effects of DES on follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL) cells in the pituitaries of male mice treated with various doses of DES for 20 days. DES reduced the density of FSH and LH cells in a dose-dependent manner, but increased that of PRL cells. When the expression of estrogen receptor (ER) alpha and beta was assessed, an induction of ERbeta by DES was found predominantly in PRL cells. However, since these effects were abolished in ERalpha knockout mice, DES appears to act primarily through ERalpha. When the expression of Ki-67 and Pit-1 in PRL cells was examined at various time-points after DES treatment, some PRL cells became Ki-67 positive at 10-15 days, and Pit-1-positive cells were increased at 5-15 days. Furthermore, some FSH and LH cells became Pit-1 positive, and co-localized with PRL at 5-10 days. Our results indicate that DES increases PRL cells by inducing proliferation of PRL cells and transdifferentiation of FSH/LH cells to PRL cells.
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ABSTRACT: It has been reported that acute exposure to diethylstilbestrol (DES) induces apoptosis in the testis, and antioxidants play a role in preventing DES-induced tissue damage. In this study, the effect of chronic exposure to DES on the antioxidants was examined in the testis and liver. Eight-week old male ICR mice were treated subcutaneously with various doses of DES for 20 days. Morphologically apparent apoptotic changes, 4-hydroxy-2-nonenal-positive cells and TUNEL-positive DNA-fragmentation, were demonstrated in the testis, but were minimal in the liver. Activities of antioxidants such as glutathione (GSH) peroxidase and GSH S-transferase decreased in both the liver and testis. The activity of Mn-superoxide dismutase (SOD) decreased in the liver but increased in the testis. The activity of Cu, Zn-SOD decreased in the liver but was unchanged in the testis. On Western and Northern blots, gamma-glutamylcysteine synthetase (gamma-GCS), a rate limiting enzyme of GSH synthesis, was increased in the liver dependent on the dose of DES. However, the expression of gamma-GCS was reduced in the testis. Since quinones, metabolites of DES, generate reactive oxygen species, which damage DNA, antioxidants are important to prevent the damage. The data suggest that antioxidant activities are impaired by DES, and the levels of GSH are related to DES-induced apoptosis in the testis.Free Radical Research 10/2002; 36(9):957-66. · 3.28 Impact Factor
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ABSTRACT: Previous immunocytochemical studies indicate that receptor regulation varies in different uterine cell types. In primates, progesterone (P) suppresses estrogen receptor (ER) in glandular epithelial cells in the functionalis, but fails to suppress ER in the glandular epithelial (GE) cells of the basalis. P also fails to suppress ER in the perivascular stromal and smooth muscle cells of the spiral arteries in the functionalis. We used nonradioactive in situ hybridization to determine whether similar cell type differences occur at the ER mRNA level. We used digoxigenin-labeled oligodeoxynucleotides (oligo-DNAs; 45-mer) as probes and detected the hybrids immunocytochemically with horseradish peroxidase-labeled antidigoxigenin antibody. This technique can discriminate between positive and negative cells in closely packed histological associations. In spayed monkeys, most of the GE cells as well as endometrial stromal cells were positive for ER mRNA, while all vascular smooth muscle, endothelium, and perivascular stromal cells were negative. Estradiol treatment for 14 days markedly increased ER mRNA staining in the GE cells, most stromal cells, and the vascular smooth muscle and perivascular stromal cells of spiral arteries in the functionalis. However, in the basalis, these components of the spiral arteries were negative as were the small basal arteries of the basalis. In most positive cells, ER mRNA was not homogeneously distributed in the cytoplasm, but, rather, was concentrated in their perinuclear regions. The GE cells in the basalis had especially intense concentrations of perinuclear signal at their apical poles. After sequential estradiol plus P treatment, the signal was greatly reduced in the GE cells of the functionalis, but not in the GE cells of the basalis or in the vascular smooth muscle or perivascular stromal cells of the spiral arteries of the functionalis. In myometrium, ER mRNA was localized to the perinuclear region of smooth muscle cells, but the staining intensity was not dramatically affected by hormonal manipulation. Unexpectedly, we observed clusters of stromal cells characterized by extremely high positive signals for ER mRNA ("hot cells") at the endometrial/myometrial border and deeper in the connective tissue of the myometrium, although such cells did not express high levels of ER protein. In general, however, the cellular distribution of ER mRNA and its hormonal regulation paralleled those of ER protein.Endocrinology 02/1993; 132(1):382-92. · 4.72 Impact Factor
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ABSTRACT: Previous work from this laboratory demonstrated that 17-beta estradiol (E2) can directly stimulate the transcription rate of the rat luteinizing hormone beta (LH beta) gene and that an upstream portion of the LH beta gene between -2.0 and -0.6 kilobases could confer an E2-stimulated response to a reporter gene in transient expression assays. To localize the LH beta estrogen response element (ERE) by biological function, portions of the 5'-flanking region of the LH beta gene or synthetic oligonucleotides were inserted in expression vectors next to the herpes simplex virus thymidine kinase promoter fused to the chloramphenicol acetyltransferase gene. Constructs were transfected into GH3 cells, and transfected cells were treated for 48 h with E2. E2 stimulation of activity (2-4-fold) occurred with constructs containing the 15-base pair palindromic sequence (GGACACCATCTGTCC), found at bases -1173 to -1159 relative to the transcriptional start site in the LH beta gene. A construct containing a synthetic oligonucleotide of this putative LH beta ERE was stimulated 1.7-3-fold by E2, while a construct containing two copies of the sequence was stimulated to a slightly higher level (2.5-4.0-fold). An oligonucleotide in which the palindrome was mutated failed to confer E2 stimulation, and mutation of the palindromic region within the upstream region of the LH beta gene also eliminated the E2 response. The anti-estrogen tamoxifen could not elicit a response, nor could dehydrotestosterone or dexamethasone; however, thyroid hormone treatment resulted in a 2-2.5-fold stimulation. The 15-base pair LH beta gene palindrome was found to bind estrogen receptor (ER) complex directly by gel retardation experiments. Labeled LH beta ERE DNA formed three complexes with proteins from immature rat uterine extract. Two of these were associated with ER complexes, as determined by the comigration of [3H] estradiol bound to ER with these complexes, and by the ability of anti-ER antibody to associate with these complexes. The affinity of the LH beta ERE for ER was calculated by Scatchard analysis to be 2.2-5.0 nM, an approximately 5-10-fold lower affinity than for the ERE in the vitellogenin A2 gene region. The mutated ERE, which had no biological activity, could not compete effectively for binding to ER. ER which was heat-transformed at 30 degrees C had a similar affinity (2-5 nM) for the ERE as ER occupied with E2 (2-4 nM), while ER occupied by estrone had a lower affinity (9 nM).(ABSTRACT TRUNCATED AT 400 WORDS)Journal of Biological Chemistry 10/1991; 266(26):17084-91. · 4.65 Impact Factor