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Biomedical subjects

R R Newbold

Publications and source records attributed to R R Newbold.

At least 73 records · Page 4Linked to original sources
PubMed1988

Immunodetection of estrogen receptor in epithelial and stromal tissues of neonatal mouse uterus.

The tissue distribution and levels of estrogen receptor in neonatal mouse uterine tissue were determined in epithelial and stromal fractions separated by mild enzymatic treatment. Proteins of the isolated fractions were separated by gel electrophoresis and receptor was detected on immunoblots with monoclonal antibody H-222. Estrogen receptor protein was detectable in samples of reproductive tract tissue from 5- and 10-day-old mice. The level of receptor in 5-day-old animals was lower per unit DNA in epithelial cells than in stroma. Receptor levels were increased in both tissue types after treatment with diethylstilbestrol, but not with progesterone. Receptor protein present in these neonatal tissues was able to bind steroid as evidenced by affinity labeling with tamoxifen aziridine. Immunohistochemistry on sections of uteri from 4- and 10-day-old mice confirmed the biochemical results and indicated lower nuclear straining in epithelial cells than in stromal cells of uteri of 4-day-old mice. These results demonstrated that estrogen receptor protein is present in both epithelium and stroma of the neonatal mouse uterus, but at a higher level in stromal cells.

Animals↗
PubMed1988

Response of the mouse uterus to nafoxidine stimulation: agonism and antagonism.

Nafoxidine (NAF) acts as an estrogen agonist or antagonist depending on the animal model used. In the CD-1 mouse uterus, a three-day uterine bioassay of NAF produced a bell-shaped dose response curve with a maximal uterine wet weight increase at 200 micrograms/kg; this dose produced only a fractional increase in uterine dry weight. Combination treatment with NAF and estradiol antagonized estradiol stimulation of both wet and dry weight parameters. The time course of uterine wet weight stimulation following a single injection of NAF had an early pattern (0-10 h) similar to that of estradiol. However, at later times after stimulation, the patterns changed dramatically: the low NAF dose (200 micrograms/kg) returned to control levels by 24 h; estradiol and the high dose NAF (1.7 mg/kg) showed sustained stimulation, which peaked at 36 h with NAF compared to 24 h for estradiol. Nuclear estrogen receptor (ER) levels were measured after a single injection of 1.7 mg/kg NAF and showed a bimodal pattern similar to that seen with estradiol, with increases at 1 h and 8 h, although the overall ER levels were elevated above those seen with estradiol. Cytosolic ER levels with NAF decreased by 1 h and remained low up to 48 h. NAF treatment did stimulate uterine DNA and RNA synthesis, with a delayed time course compared to estradiol. DNA synthesis following a single 1.7 mg/kg dose of NAF was 2.5 times higher than that produced by 20 micrograms/kg estradiol. NAF treatment resulted in hypertrophy and hyperplasia in the luminal epithelium but not in the glandular epithelium. Long-term exposure to estradiol for 5 wk resulted in development of uterine cystic glandular hyperplasia and increased secretory activity; long-term exposure to NAF produced a more significant tissue hyperplasia but no secretions. These studies show that NAF stimulates some of the receptor-mediated responses attributed to an estrogen agonist in the mouse uterus; but, when co-administered with estradiol, NAF antagonizes some aspects of estrogen action.

Animals↗
PubMed1988

Prenatal exposure of male mice to diethylstilbestrol alter the expression of the lactotransferrin gene in seminal vesicles.

We have previously isolated an estrogen-inducible secretory protein, lactotransferrin (LTF), and a cDNA to its messenger RNA from the uterus of mice. In this report we determined that the level of LTF mRNA is minimal in the seminal vesicles of normal mice. In contrast, expression of LTF mRNA in the seminal vesicles of developmentally estrogenized males was both constitutive and estrogen inducible. The results suggested that this alteration may be an example of atypical gene expression after hormonal manipulation early in development.

Androgens↗
PubMed1988

Lesions of testis and epididymis associated with prenatal diethylstilbestrol exposure.

Cryptorchidism and retention of Müllerian duct structures occur with high frequency among the male offspring of CD-1 mice treated with 100 micrograms diethylstilbestrol/kg body weight on days 9 through 16 of pregnancy. Hyperplasia of the rete testis and Müllerian duct structures were found in many of the DES-treated male mice, as was a low but significant number of reproductive tract neoplasms.

Animals↗
PubMed1987

Müllerian remnants of male mice exposed prenatally to diethylstilbestrol.

Prenatal exposure of males to diethylstilbestrol (DES) results in reproductive tract teratogenesis, ie, retention of Müllerian duct remnants. The potential of these remnants to develop pathological changes has not been studied. Therefore, pregnant outbred CD-1 mice were subcutaneously injected with daily doses of DES (100 micrograms/kg) on days 9 through 16 of gestation. DES-exposed male offspring and age-matched control male mice were sacrificed at 10 to 18 mo of age and examined for reproductive tract abnormalities. Prominent Müllerian remnants were observed in 268 out of 277 (97%) of the DES-exposed male mice. These remnants differentiated into "femalelike structures" homologous to oviduct and uterus. The Müllerian remnants were often enlarged and cystic and shared supporting connective tissue with adjacent male structures. Previously reported lesions, termed "epididymal cysts," were determined histologically to be cystic "oviductlike" structures and were, therefore, considered a Müllerian duct abnormality. Pathological changes in these male oviductal and uterine homologs included benign and malignant lesions. In addition, epididymal structures were altered. Inflammation and sperm granulomas were prevalent in DES-treated mice as young as 10 mo old but were only observed in control mice at 18 mos. Cysts of epididymal duct origin, hyperplasia, and adenoma of the epididymal duct were also observed. No comparable abnormalities were noted in 122 control males of corresponding ages. The data presented in this report demonstrated that transplacental exposure to DES affected the differentiation and normal development of the male genital tract involving both the Müllerian (paramesonephric) and Wolffian (mesonephric) ducts. The long-term changes in these tissues include lesions, some of which resembled neoplasia although the natural history of the lesions is not known. Moreover, some previously described abnormalities referred to as "epididymal cysts" were associated with tissues derived from embryonic female origin.

Animals↗
PubMed1987

Testicular tumors in mice exposed in utero to diethylstilbestrol.

Treatment of pregnant women with diethylstilbestrol (DES) is associated with the subsequent development of reproductive tract abnormalities such as epididymal cysts, retained hypotrophic testes and sperm abnormalities in their male offspring. It recently has been suggested that prenatal DES exposure is associated with development of testicular seminoma in humans. Studies of in utero exposure of laboratory animals to DES are few, but previous reports from our laboratory have described several abnormalities in the reproductive tract of the mouse following prenatal DES exposure. To study the possible association of testicular tumors and prenatal DES exposure in mice, pregnant outbred CD-1 mice were injected subcutaneously with daily doses of DES (100 micrograms./kg.) on days nine through 16 of gestation. DES-exposed and age-matched control male mice were sacrificed at 10 to 18 months of age and examined for testicular lesions. In addition to the nonmalignant abnormalities reported in previous studies such as 91% cryptorchidism and degenerative changes, interstitial cell tumors were observed in nine mice among 277 mice treated prenatally with DES. Two of these lesions were benign tumors and five were interstitial cell carcinomas. Rete testis adenocarcinoma was seen also in 5% of these DES-treated animals and is described in another report. The overall incidence of testicular tumors is 8% in DES-exposed male mice. No comparable lesions were seen in 122 control male mice. These results suggest that the testicular lesions that can occur following prenatal DES exposure include neoplasia. The combined prevalence of DES-induced tumors of the corpus testis and rete testis in mice suggests the male offspring may be more at risk for developing carcinoma of the reproductive tract than the female offspring.

Animals↗
PubMed1987

Estrogens and development.

The normal development of the genital organs of mammals, including humans, is under hormonal control. A role for the female sex hormone estrogen in this process is still unclear. However, exposure of experimental animals or humans to the potent exogenous estrogen, diethylstilbestrol (DES), results in persistent differentiation effects. Since many chemicals in the environment are weakly estrogenic, the possibility of hormonally altered differentiation must be considered.

Animals↗
PubMed1986

Paraovarian cysts associated with prenatal diethylstilbestrol exposure. Comparison of the human with a mouse model.

The association of prenatal exposure to diethylstilbestrol (DES) and abnormalities in structures of müllerian (paramesonephric) origin has been well documented. In a murine model, exposure to DES in utero results in persistent mesonephric remnants in adult female mice. Six women exposed prenatally to DES had paraovarian cysts excised during routine gynecologic surgery; and in 4, histologic abnormalities were observed, including thickened fibromuscular walls with tall columnar epithelium in a papillary or pseudoglandular configuration. Four of 25 nonexposed and 8 of 9 DES-exposed infertile women undergoing surgery for infertility had paraovarian cysts, and the difference was statistically significant (P less than 0.02). These findings raise the possibility that structures derived from the mesonephric ducts or tubules may also be affected in women exposed in utero to DES.

Animals↗
PubMed1986

Absence of estrogenic activity in some drugs commonly used during pregnancy.

Treatment of pregnant women with estrogenic compounds such as diethylstilbestrol (DES) has been associated with genital tract abnormalities in their male and female offspring. Since these data suggest the developing fetus is highly susceptible to the tumorigenic and dysmorphogenic effects of estrogenic substances, knowledge of the estrogenic activity of some drugs commonly used during pregnancy is important. Based on structural similarities to other known estrogenic compounds and to the frequency of use among pregnant women, phenobarbital, saccharin and acetaminophen were assayed for estrogenic activity; DES was used as a positive control. Using a competitive receptor binding assay, these compounds did not show appreciable binding to a soluble uterine receptor preparation while DES showed strong binding interactions. Analysis of the compounds in an in vivo uterotropic bioassay using immature female mice showed that, over the dose range used (5 micrograms/kg-50 micrograms/kg), only DES had any estrogenic activity while the other compounds were negative. Therefore, phenobarbital, saccharin and acetaminophen did not display estrogenic activity under the conditions of test.

Acetaminophen↗
PubMed1985

Progressive proliferative changes in the oviduct of mice following developmental exposure to diethylstilbestrol.

Structural malformation of the oviduct has been reported in experimental animal models and women following prenatal exposure to diethylstilbestrol (DES). To study histological changes in the oviduct in the absence of gross structural malformation, neonatal CD-1 mice were treated with DES (2 micrograms/pup/day) on days 1-5 of age. Focal epithelial hyperplasia was present at 1 month of age in 16 out of 18 (89%) of the DES-treated mice. At 4 months of age, general epithelial hyperplasia with multiple gland-like structures into and through the muscle wall of the oviduct was observed in 90% of the treated mice; by 12 months of age, epithelial hyperplasia and pseudogland formation were seen in 100% of the DES-exposed animals. Epithelial hyperplasia and gland formation were not observed in control mice. The alteration induced by DES in the differentiation and proliferation of mouse oviductal epithelium suggests that the oviduct is a target for DES toxic effects. In addition, there was a progression of the epithelial changes with age. The histological changes described in this study may be partially responsible for the decreased fertility previously reported in this mouse model. Similar changes in the oviduct of DES-exposed women remain to be determined.

Aging↗
PubMed1985

Prenatal diethylstilbestrol exposure alters murine uterine responses to prepubertal estrogen stimulation.

Prepubertal estrogen stimulation was used to investigate the effects of prenatal diethylstilbestrol (DES) exposure on subsequent growth, secretory activity, and cellular differentiation of the mouse uterus in vivo. Secretory activity was examined using sensitive silver staining of two-dimensional gel electrophoresis of uterine luminal fluid (ULF). Decreased uterine growth response, decreases in ULF quantity and protein concentration, alterations in specific ULF proteins, and altered cellular differentiation were found. This system provides a method for evaluation of the effects of prenatal exposure to DES or other compounds on the estrogen-induced secretory activity of the uterus. The alterations found in this study may be partially responsible for the decreased fertility in this mouse model and may have implication for DES-exposed women.

Animals↗
PubMed1985

Lesions of the rete testis in mice exposed prenatally to diethylstilbestrol.

Adenocarcinoma of the rete testis is an exceptionally rare and malignant testicular neoplasm. Although treatment of pregnant women with diethylstilbestrol (DES) results in reproductive tract abnormalities in their male offspring, increased incidence of testicular tumors has not been verified. However, recently three cases of seminoma have been described in men prenatally exposed to DES, suggesting an association of prenatal DES treatment and the subsequent development of testicular tumors. This report describes the treatment of outbred pregnant CD-1 mice with DES (100 micrograms/kg) on Days 9 through 16 of gestation and its effects on their male offspring. In addition to nonmalignant abnormalities such as retained testes which have been reported in men exposed prenatally to DES, lesions resembling adenocarcinoma of the rete testis were seen in prenatally DES-treated mice at 10 to 18 mo of age (11 of 233; 5%). No comparable lesions were seen in 96 age-matched control male mice. These results suggest an association of prenatal DES exposure and the subsequent development of testicular lesions in the rete testis of mice.

Adenocarcinoma↗
PubMed1984

Diethylstilbestrol and other estrogens in the environment.

Many environmental agents of diverse chemical structure possess estrogenic activity. Other hormonal activities do not seem to be so widespread through different chemical classes. Some compounds such as the mycotoxin, zearalenone, are metabolized from weakly active to more estrogenic forms and may thus be considered proestrogens. Metabolism of potent xenobiotics, such as diethylstilbestrol (DES), may result in relatively less hormonally active compounds as well as reactive intermediates associated with long-term toxicities. Weakly estrogenic xenobiotics may be physiologically significant if they persist in the body or when there is continuous exposure; some compounds with no apparent estrogen-receptor-binding affinity may exert estrogenic effects through indirect mechanisms. Estrogenic materials as part of the environment derive from natural (e.g., plant estrogens or mycotoxins) and synthetic (e.g., DES or DDT) sources. In some cases, environmental compounds may be potent estrogens which are used for their hormonal activity, or in other cases, they are weak estrogens in which hormonal activity is an inadvertant function; an example of the former case is DES as a growth-promoting agent for cattle, an example of the latter, kepone. Elucidation of the structural basis of estrogenic activity is the critical step awaited in this area.

Animals↗
PubMed1984

Molecular differentiation of the mouse genital tract: altered protein synthesis following prenatal exposure to diethylstilbestrol.

Exposure in utero to the synthetic estrogen diethylstilbestrol (DES) has been associated with the subsequent development of reproductive tract lesions in both women and experimental animals. Using the techniques of organ culture and two-dimensional (2-D) gel electrophoresis, the effects of DES on protein synthetic patterns were studied during fetal and neonatal development of the CD-1 mouse. The protein patterns, analyzed by comparing 2-D fluorograms after [35S] methionine incorporation at different developmental stages, were correlated with the histology at the same age. Several qualitative and quantitative changes in protein synthesis were observed after prenatal DES exposure. A protein, apparent by Day 14 of gestation, with molecular weight approximately 70,000 and pI of 5.8, was observed to be greatly diminished in all reproductive tract tissues exposed to DES during prenatal development. This alteration, induced in utero, persists through the early postnatal differentiation of the genital tract (17 days old). This protein may provide an early marker for alterations in normal reproductive tract function.

Animals↗
PubMed1984

Prenatal diethylstilbestrol exposure in the mouse: effects on ovarian histology and steroidogenesis in vitro.

The effect of prenatal diethylstilbestrol (DES) exposure on ovarian morphology and steroid production in vitro was evaluated in the mouse. Pregnant mice were injected with 100 micrograms DES per kg maternal body weight on Days 9 to 16 of gestation and the female offspring sacrificed from 3 to 14 months of age. Ovaries of DES-exposed animals weighed significantly less than controls at 3 months of age (9.4 +/- 0.79 mg vs. 17.54 +/- 0.69 mg, mean +/- SEM). Histologically, the DES animals had an apparent increase in the size of the interstitial compartment with cells showing uniform vacuolization and tubular architecture. In addition, the lipid content of the interstitial compartment, as assessed by oil-red-O staining, was markedly increased in the treated animals as compared to controls and corresponded to the vacuolization. Ovarian steroidogenesis in vitro was determined by excising ovaries of animals from 3 to 14 months of age, placing them in tissue culture for 24 h, and measuring media steroids by radioimmunoassay. Estrogen, progesterone and testosterone production per mg of tissue was increased in DES-exposed animals at all ages studied. To correct for changes in the relative sizes of the ovarian compartments secondary to DES exposure, steroid production was calculated on a "per ovary" basis. Only testosterone production remained elevated "per ovary" in the DES-exposed animals which is consistent with androgens being the primary secretory products of the enlarged interstitial compartment. These data indicate that in the mouse, prenatal DES exposure is associated with an enlargement of the ovarian interstitial compartment, increased lipid content of the individual interstitial cells, and increased interstitial compartment testosterone production in vitro throughout the reproductive life span of the animal.

Animals↗
PubMed1984

Müllerian duct maintenance in heterotypic organ culture after in vivo exposure to diethylstilbestrol.

Prenatal exposure to diethylstilbestrol (DES) results in the persistence of Müllerian ducts in male offspring. The influence of DES on Müllerian duct regression was studied using an organ culture system in which DES-treated or control indifferent ducts (embryonic reproductive tracts) were cocultured along with treated or control embryonic testes. Prenatal DES exposure was by sc injection of the mother (100 micrograms/kg BW) on days 9 through 12 of gestation. Embryonic tissues were removed on day 13 of gestation and cultured for 72 h. In organ culture, Müllerian duct regression, comparable to that seen in vivo, occurred when control reproductive tracts were associated with control testes. However, maintenance of the Müllerian duct was observed in 100% of the tissues when DES-treated testes and DES-treated reproductive tracts were cultured together. When recombinations were formed by the association of control reproductive tracts and DES-treated testes, there was regression of the Müllerian duct (87%). However, in the combinations of DES-treated reproductive tracts and control testes, 41% of the cultured tissue demonstrated partial regression of the Müllerian duct, and 59% showed no regression. These data support previous in vivo results that prenatal exposure to DES has an inhibitory effect on Müllerian duct regression and further suggest that this inhibitory effect is mainly due to a decrease in responsiveness of the treated embryonic Müllerian duct.

Animals↗