Psychosexual milestones in women prenatally exposed to diethylstilbestrol

Thirty women aged 17 to 30 years with a record-confirmed history of prenatal exposure to diethylstilbestrol (DES) were compared to 30 women of similar age and demographic background with a history of abnormal Pap smear findings. Heterosocial and heterosexual histories were assessed by systematic semistructured interviews. The groups differed neither in the age at menarche nor in the age at attainment of various psychosexual milestones.     

Altered glutathione homeostasis in heart augments cardiac lipotoxicity associated with diet-induced obesity in mice

Obesity-related cardiac lipid accumulation is associated with increased myocardial oxidative stress. The role of the antioxidant glutathione in cardiac lipotoxicity is unclear. Cystathionine β-synthase (Cbs) catalyzes the first step in the trans-sulfuration of homocysteine to cysteine, which is estimated to provide ～50% of cysteine for hepatic glutathione biosynthesis. As cardiac glutathione is a reflection of the liver glutathione pool, we hypothesize that mice heterozygous for targeted disruption of Cbs (Cbs(+/-)) are more susceptible to obesity-related cardiolipotoxicity because of impaired liver glutathione synthesis. Cbs(+/+) and Cbs(+/-) mice were fed a high fat diet (60% energy) from weaning for 13 weeks to induce obesity and had similar increases in body weight and body fat. This was accompanied by increased hepatic triglyceride but no differences in hepatic glutathione levels compared with mice fed chow. However, Cbs(+/-) mice with diet-induced obesity had greater glucose intolerance and lower total and reduced glutathione levels in the heart, accompanied by lower plasma cysteine levels compared with Cbs(+/+) mice. Higher triglyceride concentrations, increased oxidative stress, and increased markers of apoptosis were also observed in heart from Cbs(+/-) mice with diet-induced obesity compared with Cbs(+/+) mice. This study suggests a novel role for Cbs in maintaining the cardiac glutathione pool and protecting against cardiac lipid accumulation and oxidative stress during diet-induced obesity in mice.     

Reproductive aspects in female rats exposed prenatally to hydrocortisone

We investigated the effects of hydrocortisone during the prenatal period and its later repercussion on reproductive aspects of female rats. Pregnant rats were treated (s.c.) with hydrocortisone acetate, at 1.5 mg/day on the 17th, 18th, and 19th days of pregnancy. Although the present study was not intended to identify mechanisms of toxicity, the treatment with hydrocortisone in the last period of pregnancy presented no signs of toxicity. The efficacy of the hydrocortisone in reducing the adrenal wet mass and plasma corticosterone levels immediately after delivery in both the treated mothers and in respective pups at birth may indicate impairment of the hypothalamus-pituitary-adrenal axis. In addition, the treatment with hydrocortisone did not interfere in the development of the female descendants until puberty. However, it affected the estrous cycle and fertility. Probably, the prenatal exposure to corticosteroids had altered at least partially the hypothalamus-pituitary-gonadal axis, resulting in the damages observed in adult life. These results indicate that the use of the hydrocortisone at a dose that apparently does not endanger the neonate led to undesirable effects in the adult reproductive phase, resulting in later deleterious alteration of the reproductive physiology in female rats.     

Complications of pregnancy in mice exposed prenatally to DES

Women exposed prenatally to diethylstilbestrol (DES) develop a variety of reproductive tract anomalies. Most of these anomalies have been replicated in strain CD-1 mice after similar DES exposure. Recently, impaired reproductive performance in DES-exposed women has been reported. To see whether the mouse model also replicates this defect, a study of reproduction was performed. Pregnant CD-1 mice were injected with DES and their female offspring were raised to breeding age. The latter were then exposed continuously to untreated males for a maximum of 4 months. Among 74 mated mice, 34 became pregnant and 11 of these pregnancies ended in abortion or stillbirth. Other anomalies encountered were: two fetuses with compressed heads, one of which seemed blocked from delivery by a vaginal adenocarcinoma; two uterine tumors, one of which was a teratocarcinoma; two teratomas located in uterine lumina; and two uteri containing placentas without embryos. Since the frequency of successful pregnancies in the DES-exposed mice was reduced below control levels to a degree similar to that reported for DES-exposed women, the validity of the mouse model has been confirmed for this characteristic.     

Craniofacial alterations in adult rats prenatally exposed to ethanol

The rat was studied to determine whether gestational exposure to moderate amounts of ethanol produces permanent craniofacial malformations. Pregnant Long-Evans rats were fed a liquid diet containing 35% ethanol-derived calories or an isocaloric liquid diet between gestation days 6 and 20. Various dimensions of skulls and mandibles from adult male offspring were measured. All measurements taken in the parasagittal and coronal planes were significantly smaller in the ethanol-exposed rats than in the offspring of pair-fed controls. None of the vertical measurements was significantly altered. This report demonstrates that gestational exposure to ethanol in rats, at doses which produce lasting behavioral effects, also produces a specific constellation of craniofacial dysmorphisms without concomitant decreases in body weight.     

Sexual development and performance in boars exposed prenatally to triamcinolone

The objectives of this study were 1) to investigate the effects of triamcinolone exposure prenatally upon the gonadotropin-gonadal system and 2) to determine whether prenatal exposure affects the onset of puberty and postpuberal development in boars. Two or four litter-mate Yorkshire boars were randomly selected from five litters from sows fed unsupplemented diets and from seven litters from sows fed triamcinolone-supplemented diets. The boars were studied from birth through 30 wk of age. During this 30-wk period, the boars were bled once every 4 wk and testicular and body weight measurements were taken every 2 wk. From weeks 20 to 30 the boars were exposed weekly to an estrous gilt. During this time, the onset and frequency of mounting and ejaculation were recorded and the quality of the semen collected was evaluated. At slaughter, additional data on the male reproductive tract were collected. The prepartal feeding of triamcinolone to sows did not affect either the boars' weight gain or testicular volume during the 30-wk experimental period. Plasma concentrations of testosterone or cortisol also did not differ (P > 0.10) between the groups of boars. However, mounting and ejaculation occurred earlier in triamcinolone-exposed boars, suggesting that prepartal treatment of sows with triamcinolone may have enhanced the development of sexual behavior and onset of puberty in their offspring.     

Taste aversion learning in preweanling rats exposed to alcohol prenatally

The effects of prenatal alcohol exposure on the development of a conditioned taste aversion were examined in preweanling rat pups. Mothers of these pups were fed isocaloric liquid diets containing either 35 or 0% ethanol-derived calories (EDC) from gestation days 6 through 20. A pair-feeding procedure was employed, and an ad lib lab chow control group was also included. At 5, 10, or 15 days of age, pups were infused with a saccharin solution through a cannula implanted in the oral cavity. Half of the pups in each group were then injected with lithium chloride (LiCl), which served as the poisoning agent, and the other half with sodium chloride (NaCl) as a control. Animals were subsequently tested for a conditioned aversion to the saccharin solution. At 15 days of age, all of the pups in the LiCl-poisoned group demonstrated a conditioned taste aversion to the saccharin solution, but the degree of this aversion was less in alcohol-exposed offspring. At 10 days of age, a taste aversion was learned, although it was not as strong as that shown by 15-day-old pups, and it appeared to be learned equally well by all of the prenatal treatment groups. At 5 days of age, there was marginal support for taste aversion learning. Again, it did not interact with prenatal treatment. The ontogenic differences in taste aversion learning exhibited by alcohol-exposed offspring relative to controls are discussed in terms of altered hippocampal development.     

Temporary increase in chromosome breakage in an infant prenatally exposed to lead

Summary An infant exposed to high levels of lead in utero was found to have increased numbers of cells with chromosome breaks in blood samples obtained at 6 weeks and 3 months of life. Later samples did not show significant abnormality. Physical and neurological examinations of the patient up to 18 months of age gave results within normal limits.     

Induction of glutathione S-transferase activity and glutathione level in plants exposed to glyphosate

Treatment with the herbicide glyphosate led to significantly increased activities of the enzyme gluiathione S-transferase (GST, EC 2.5.1.18) in wheat ( Triticum aestivum L. cv. Kadett and cv. Satu), pea ( Pisum sativum L. ev. Debreceni Világoszöld) and in maize ( Zea mays. L. Pioneer 3839 hybrid) tissues. GST activities in wheat seedlings (cv. Kadett) exposed to 960 μM glyphosate for 4 days were ca 6-fold and 3-fold higher in shoots and roots, respectively, than in the controls. Glyphosate increased the GST activity to a lesser extent in pea and maize than in wheat. In wheat seedlings (cv. Satu) exposed let 120 μM glyphosate gradual increases in the content of non-protein thiols were observed. After 7 days exposure to glyphosate the thiol levels rose to about 360% and 220% of the controls in wheal shoots and roots, respectively. The elevation of thiol content in glyphosate-treated plants was shown to be primarily due increases of glutathione level. These results suggest that the enhanced glutathione metabolism may have a role in the mode of action or degradation of this herbicide.     

Increased glutathione content in yeastSaccharomyces cerevisiae exposed to NaCl

Glutathione is one of the major antioxidant molecules of cells and is thought to play a vital role in buffering the cell against reactive oxygen species and toxic electrophiles. Since an overlap between osmotic and oxidative stress response is already know, the aim of the work was to determine the role of glutathione in yeast stress response to NaCl. YeastSaccharomyces cerevisiae ZIM 2155 was exposed to NaCl in concentration of 1–8% (w/v). Measuring cell cultivability showed a significant decrease appeared in cell exposed to 5–8% NaCl for 1 h. Cultivable cells were about 50% of control. Increased production of reactive oxygen species in cells exposed to 6, 7 and 8% NaCl for 1 h (1.3-fold, 1.9-fold and 2.8-fold increase, respectively) led to elevated glutathione content in reduce d form (119.1%, 122.6%, 141.5%, respectively). Two hours from NaCl addition intracellular oxidant level was slightly elevated compared to 1-h exposure, while glutathione content in reduced form was almost the same. We demonstrated that glutathione plays an important role in yeast stress response to NaCl.     

Developmental changes in intestinal brush border enzymes of rats prenatally exposed to ethanol

The activities of lactase, sucrase, alkaline phosphatase (AP) and y-glutamyl transpeptidase (gamma-GTP) were studied in the intestinal brush border membranes of pups born to rat mothers exposed to ethanol (1 ml of 30% ethanol daily during gestation) at different days of postnatal development. The activities of lactase (at day 4-20) and sucrase (at day 20-30) were considerably reduced in response to prenatal exposure to ethanol, while AP (at day 4-30) and gamma-GTP activities were significantly enhanced (p < 0.05) at day 4, 8, 14 and 20, but there was no significant difference by day 30 of postnatal development. The observed changes in enzyme activities were corroborated by Western blot analysis of lactase, sucrase and AP. Kinetic studies revealed a change in Vmax without affecting apparent Km of enzymes under these conditions. The present findings suggest that in utero ethanol exposure to rats is embryotoxic and affects the postnatal development of various brush border enzymes, which persist long after the ethanol was withdrawn prior to birth.     

Renal glutathione homeostasis in compensatory renal growth

Glutathione homeostasis was investigated in unilaterally nephrectomized and sham-operated rats. Following twelve days of compensatory renal growth, it was found that the concentrations of glutathione and glutathione disulfide in representative samples of the entire remnant right kidney from the nephrectomized rats were similar to those found in corresponding samples of the right kidneys from the sham-operated rats. However, since the mass of the remnant right kidneys in the nephrectomized rats was greater than that of the right kidneys from the sham-operated rats, the absolute content of glutathione and glutathione disulfide was greater in the remnant right kidneys of the nephrectomized rats than in the right kidneys of the sham-operated rats. In general, the findings from the present study indicate that the absolute content of glutathione and glutathione disulfide in renal epithelial cells increases in proportion to the increase in mass that results from compensatory renal cellular hypertrophy.     

A functional transsulfuration pathway in the brain links to glutathione homeostasis

Oxidative stress and diminished glutathione pools play critical roles in the pathogenesis of neurodegenerative diseases, including Alzheimer and Parkinson disease. Synthesis of glutathione, the most abundant mammalian antioxidant, is regulated at the substrate level by cysteine, which is synthesized from homocysteine via the transsulfuration pathway. Elevated homocysteine and diminished glutathione levels, seen in Alzheimer and Parkinson disease patients suggest impairments in the transsulfuration pathway that connects these metabolites. However, the very existence of this metabolic pathway in the brain is a subject of controversy. The product of the first of two enzymes in this pathway, cystathionine, is present at higher levels in brain as compared with other organs. This, together with the reported absence of the second enzyme, gamma-cystathionase, has led to the suggestion that the transsulfuration pathway is incomplete in the brain. In this study, we incubated mouse and human neurons and astrocytes and murine brain slices in medium with [35S]methionine and detected radiolabel incorporation into glutathione. This label transfer was sensitive to inhibition of gamma-cystathionase. In adult brain slices, approximately 40% of the glutathione was depleted within 10 h following gamma-cystathionase inhibition. In cultured human astrocytes, flux through the transsulfuration pathway increased under oxidative stress conditions, and blockade of this pathway led to reduced cell viability under oxidizing conditions. This study establishes the presence of an intact transsulfuration pathway and demonstrates its contribution to glutathione-dependent redox-buffering capacity under ex vivo conditions in brain cells and slices.     

Genetically altered mice to evaluate glutathione homeostasis in health and disease

The tripeptide glutathione (GSH) is part of an integrated antioxidant system that protects cells and tissues from oxidative damage. Oxidative stress can result from exposure to excessive amounts of endogenous and exogenous electrophiles. Until recently, animal and cell model systems used to investigate the role of GSH in disease processes had employed chemical agents that deplete cellular GSH by inhibiting GSH synthesis or by reacting chemically with GSH. Such models have proven useful, but questions concerning nonspecific effects of such chemicals remain. Recently, our laboratories and others have developed mouse models with genetic deficiencies in enzymes of the GSH biosynthetic pathway. This review focuses on the regulation of GSH homeostasis and, specifically, the new GSH-deficient mouse models that have been developed. These models will improve our understanding of the role of GSH in animal and human diseases.     

Selenium modifies glutathione peroxidase activity and glutathione concentration in mice exposed to ozone-provoked oxidative stress

The aim of this study was to show the direct effect of selenium on glutathione peroxidase (GSH-Px) activity and GSH/GSSG concentrations in 3- and 6-month-old mice. An ozone-oxygen mixture was used to provoke an oxygen stress. To measure the Se-effect mice were gavaged with sodium selenite. GSH-Px activity and total glutathione concentrations were determined in serum and in the postnuclear fraction of liver and lungs. Additionally glutathione concentrations were determined in whole blood. Both ozone and selenium, administered separately, reduced GSH-Px activity in lungs of 6-month-old animals, while in young mice an opposite effect of Se was observed. Ozone administered jointly with Se did not influence GSH-Px activity in 6-month-old mice, while in young, 3-month-old mice, a stimulatory effect in lungs was observed. There were no significant changes in GSH-Px activity in the liver of 6-month-old mice, but the stimulatory effect occurred in young mice treated with Se and Se & ozone jointly. In young mice, ozone (also ozone with Se) augmented glutathione concentrations. The response to ozone and selenium strictly depended on age and the antagonism between selenium and ozone was observed only in a few cases.     

Altered iron homeostasis involvement in arsenite-mediated cell transformation

Chronic exposure to low doses of arsenite causes transformation of human osteogenic sarcoma (HOS) cells. Although oxidative stress is considered important in arsenite-induced cell transformation, the molecular and cellular mechanisms by which arsenite transforms human cells are still unknown. In the present study, we investigated whether altered iron homeostasis, known to affect cellular oxidative stress, can contribute to the arsenite-mediated cell transformation. Using arsenite-induced HOS cell transformation as a model, it was found that total iron levels are significantly higher in transformed HOS cells in comparison to parental control HOS cells. Under normal iron metabolism conditions, iron homeostasis is tightly controlled by inverse regulation of ferritin and transferrin receptor (TfR) through iron regulatory proteins (IRP). Increased iron levels in arsenite transformed cells should theoretically lead to higher ferritin and lower TfR in these cells than in controls. However, the results showed that both ferritin and TfR are decreased, apparently through two different mechanisms. A lower ferritin level in cytoplasm was due to the decreased mRNA in the arsenite-transformed HOS cells, while the decline in TfR was due to a lowered IRP-binding activity. By challenging cells with iron, it was further established that arsenite-transformed HOS cells are less responsive to iron treatment than control HOS cells, which allows accumulation of iron in the transformed cells, as exemplified by significantly lower ferritin induction. On the other hand, caffeic acid phenethyl ester (CAPE), an antioxidant previously shown to suppress As-mediated cell transformation, prevents As-mediated ferritin depletion. In conclusion, our results suggest that altered iron homeostasis contributes to arsenite-induced oxidative stress and, thus, may be involved in arsenite-mediated cell transformation.