摘要:

The ethanol‐inducible cytochrome P4502E1 (2E1) is involved in the bioactivation of numerous hepatotoxins and hepatocarcinogens. Because high levels of expression may enhance the degree and severity of hepatotoxicity from exposure to chemicals metabolized by this enzyme, a relatively noninvasive method to phenotypically distinguish those individuals exhibiting elevated concentrations of 2E1 may be useful. With this in mind, we examined whether ethanol exposure could alter 2E1 in rabbit white blood cells and liver in a similar manner. Microsomes prepared from freshly isolated, rather than cultured cells, were used to immunochemically detect 2E1. The enzyme was found in lymphocytes and neutrophils. Lymphocytes, which comprise the majority of the white cell population in rabbits, were monitored for changes in 2E1 protein levels after ethanol exposure and compared with alterations of the hepatic enzyme. Results presented herein demonstrate that the degree of enhancement in 2E1 expression of lymphocytes and liver was dependent on the length and dose of alcohol exposure. Indeed, correlations were observed between blood alcohol concentrations and 2E1 content in lymphocytes (r= 0.65,p<0.01) and liver (r= 0.60,p<0.01). The greatest increase in 2E1 (6‐ to 10‐fold) occurred in both liver and lymphocytes at a dose of 15% ethanol for 12 days of treatment. This induction was evident regardless of whether blood was taken from treated and compared with untreated rabbits or if white cells were obtained from the same animal before and after ethanol exposure. The latter findings demonstrate that changes in lymphocyte 2E1 were caused by ethanol exposure and not to variability in enzyme expression among rabbits. Interestingly, at the 10% dose, elevation of 2E1 was noted as early as 3 days, declined at 6 days, and at 12 and 24 days returned to slightly higher levels than those seen at the 3‐day exposure period. This pattern of 2E1 elevation was observed in both the liver and lymphocytes, in fact, at all exposure periods and at the two doses of alcohol examined, a correlation (r= 0.70,p<0.01) was observed between lymphocyte and liver 2E1 content. Collectively, these studies show that induction of 2E1 in lymphocytes and liver occurs in a parallel fashion. Furthermore, results suggest that blood 2E1 may be used in humans as a phenotypic marker for xenobiotic‐promoted alterations in the expression of the liver enzyme. These findings should have a significant impact on in vivo monitoring of this P4

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb00994.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The mechanism by which prenatal ethanol ingestion causes fetal alcohol syndrome (FAS) is unknown. We hypothesize that ethanol disrupts the normal function of retinoids in embryogenesis and differentiation, resulting in FAS. The present work was designed to determine if prenatal ethanol ingestion affects the expression of cellular retinol binding protein (CRBP) and nuclear retinoic acid receptors (RARs). Paired timed pregnant rats were fed a liquid diet, one group treated with 36% of carbohydrate calories replaced with ethanol. Maternal serum retinol concentrations during pregnancy peaked on the 6th day of pregnancy, but no difference was noted between the ethanol and control group. At the 12th and 20th day of gestation, embryos or fetal brain were removed, and RNA was isolated for Northern hybridization. The abundance of CRBP mRNA was significantly elevated by ethanol consumption in both the 12‐day embryo (relative density of control: 1.00 ± 0.10; vs. ethanol: 1.87 ± 0.30,p<0.05) and 20‐day fetal brain (relative density of control: 1.00 ± 0.09; vs. ethanol: 1.46 ± 0.09,p<0.01). In the embryo, ethanol ingestion resulted in a decrease in the level of RAR‐β mRNA (control: 1.00 ± 0.05; vs. ethanol: 0.71 ± 0.07,p<0.01), but had no effect on RAR‐α or RAR‐γ mRNA. In contrast to the embryo, the expression of both the 3.7‐ and 2.7‐kb RAR‐α transcripts was significantly greater in day 20 fetal brain of ethanol‐treated rats (3.7‐kb RAR‐α control: 1.00 ± 0.11; vs. ethanol: 1.65 ± 0.06;p<0.001;2.7‐kb RAR‐α control: 1.00 ± 0.14; vs. ethanol: 1.74 ± 0.27,p<0.05), whereas RAR‐β and RAR‐γ expression were not altered. These observations suggest that altered vitamin A function is a potential factor

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb00995.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

In this study, luteinized human granulosa cells (GC) obtained during in vitro fertilization procedures were used as a model system to evaluate the effects of ethanol (EtOH), a well‐known reproductive toxin, on epidermal growth factor (EGF) and gonadotropin‐stimulated steroidogenesis. Our results demonstrate that the basal progesterone (P4) and estradiol (E2) secretion by human GC in vitro was dependent on the ovarian stimulation protocol. EGF significantly enhanced P4, but not E2, secretion in human GC from clomiphene citrate (CC), human menopausal gonadotropin (hMG), and hMG/gonadotropin‐releasing hormone agonist (GnRH‐a)‐treated patients. The effects of EGF plus luteinizing hormone (LH) were additive in cells from the CC group, but less than additive in hMG and hMG/GnRH‐a groups. EtOH at 20 mM or more inhibited EGF stimulated P4secretion in human GC from all three patient groups. EtOH inhibited P4secretion stimulated by EGF and LH cotreatment in the CC and hMG/GnRH‐a groups, but not in human GC from the hMG‐treated patients. These results suggest that basal and EGF or LH‐stimulated P4secretion by human GC, as well as the effects of EtOH, are profoundly influenced by the follicle'

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb00996.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The present study examined fetal alcohol effects (FAE) on the induction of the immediate early genes (IEGs) c‐fos, jun B, c‐jun, and zif268 mRNAs in the prefrontal cortex, hippocampus, and other brain regions after testing in an alternation task. Subjects were female offspring of Sprague‐Dawley rats fed either a 35% ethanol‐derived calorie diet, pair‐fed with sucrose, or control‐fed with laboratory chow during the last week of gestation. At 75–85 days of age, rats were food‐deprived and trained in a t‐maze for food reward. Then rats were tested at 5‐sec, 30‐sec, or 60‐sec delays on each of 6 days. On the day of killing, a subset of rats was tested at the 60‐sec delay for 12 trials and killed 30 min after testing. The remaining animals were killed from their home cage and acted as controls. Expression of the four IEG mRNAs was examined in the brains of these animals using in situ hybridization. FAE rats showed a memory deficit at the 60‐sec delay (p<0.05), but not at the 0‐sec or 30‐sec delays. Testing in the alternation task induced a significant elevation of c‐fos, c‐jun, jun B, and zif268 mRNA expression in the prefrontal cortex, hippocampal subfields CA1 and CA3, and several cortical areas. However, FAE rats showed a significantly smaller elevation of both c‐fos and jun B mRNA levels in the orbital, prelimbic, and anterior cingulate regions of the prefrontal cortex (p<0.05). FAE animals also showed a lower expression of jun B mRNA in the caudate nucleus. Significant correlations between the mean performance at the 60‐sec delay and mRNA expression of c‐fos, jun B, and zif268 in the prefrontal cortical regions (p<0.05) were observed. These findings suggest that fetal alcohol exposure produces changes in the adult prefrontal cortex that may contribute to the b

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb00997.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Glucose transport was studied in primary hippocampal neuron cultures exposed to ethanol. Immunofluorescent staining with antibodies against neuron‐specific enolase and glial fibrillary acidic protein identified ∼95% of the cultured cells as neurons. Western blot analysis was conducted with polyclonal antisera to glucose transporter isoforms GLUT1 and GLUT3. As previously seen in astrocytes, GLUT1 protein was regulated by the culture medium glucose content. Exposure to 50 and 100 mM of ethanol for 5 hr induced dose‐dependent reductions in GLUT1 and GLUT3 protein. In contrast, GLUT1 mRNA abundance was increased relative to controls under the same conditions. Glucose uptake, measured with the nonmetabolized analog, 2‐deoxy‐d‐glucose, was reduced by 50 and 100 mM of ethanol in four experiments. These results indicate a direct effect of ethanol on neuronal glucose transporter expression, which may play a role in the neurotoxic effects

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb00998.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Acute ethanol (EtOH) in vivo decreases both the pressure of the lower esophageal sphincter (LES) and the amplitude of contractions of the smooth muscle of the lower esophageal body (LEB) in both man and cat. However, the mechanism of this inhibitory effect of EtOH is unclear. This inhibitory effect could be caused by a direct effect of EtOH on the esophagus or be secondary to known inhibitory effects of EtOH on the central nervous system. To this end, we evaluated the in vitro effect of EtOH on contractility of smooth muscle strips from both LES and LEB. Circular muscle strips from LES and LEB were isolated from cats. Changes in resting tension of LES strips and changes in stimulant‐induced tension of LES or LEB strips were measured in the presence of up to five concentrations of EtOH (12.5–100 mM). Stimulants included electric field stimulation (EFS) and carbachol. EtOH at 75 mM significantly decreased resting LES tension. EtOH also decreased maximal contractile responses to carbachol in both LES and LEB and increased the EC50of carbachol for LES, but not LEB. EtOH also modulated EFS‐induced esophageal contractility; EtOH potentiated EFS‐induced “on‐response relaxation” in LES and decreased EFS‐induced “off‐response contractions” in LEB. EtOH‐induced inhibition of esophageal contractility seemed to be reversible. EtOH did not result in muscle fatigue. Thus, EtOH can directly inhibit contractility of the esophagus, and does so reversibly and at pharmacologically

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb00999.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

We studied the effect a variety of hormones and chemical stimuli on the activity of lowKmaldehyde dehydrogenase (ALDH) in rat H4IIEC3 hepatoma cells and ALDH activity in human HuH7 hepatoma cells. The lowKmenzyme in H4IIEC3 cells reflects ALDH2 activity, and the ALDH activity in HuH7 likely represents ALDH5. Of the steroid hormone family, thyroid hormone, progesterone, and dihydrotestosterone increased lowKmALDH activity ∼50%, whereas dexamethasone and estradiol had little effect. Insulin decreased the activity of lowKmALDH. None of these hormones affected the activity of ALDH in HuH7 cells. Among second messengers, 8‐bromo‐cAMP and A23187 increased lowKmALDH activity; HuH7 ALDH activity again was unchanged. Exposure of the cells to 22 mM ethanol reduced lowKmactivity by ∼20%, whereas hydrogen peroxide, tumor necrosis factor‐α, and interleukin‐β had little effect. Ultraviolet light increased the HuH7 ALDH activity. Retinaldehyde or retinoic acid reduced the HuH7 ALDH activity, but had no effect on lowKmALDH activity. These data suggest that lowKmALDH2 can be regulated by hormones and may not be constitutive as previously thought, and that the HuH7 ALDH is regulate

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb01000.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The contents of dopamine (DA), 3,4‐dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5‐HT), and 5‐hydroxy‐indoleacetic acid (5‐HIAA) were determined in the nucleus accumbens (ACB), frontal cortex (FR), anterior striatum (AST), and hippocampus (HIP) of adult male rats from the F2generation of P×NP intercrosses. Rats were tested for their alcohol preference and were divided into two groups, depending on their alcohol intake. Rats in the high drinking group (n= 11) had ethanol intakes>5 g/kg/day, whereas the low drinking group (n= 15) had values<1 g/kg/day. The content of DA in the ACB was lower (p<0.001) in the high alcohol drinking group (46 ± 2 pmol/mg tissue) than in the low intake rats (61 ± 3 pmol/mg tissue). However, the contents of DOPAC and HVA in the ACB were similar for both groups. There were no differences between the two groups in the contents of DA in the FR or AST. The content of 5‐HT in the ACB was lower (p<0.05) in high alcohol drinking rats (6.3 ± 0.3 pmol/mg tissue) than in the low intake group (7.0 ± 0.2 pmol/mg tissue). The content of 5‐HIAA in the ACB of the high intake rats was also lower than the level for the low drinking rats. There were no differences in the contents of 5‐HT or 5‐HIAA in the FR, HIP, and AST between the two groups. The results confirm a phenotypic association between abnormal DA and 5‐HT systems projecting to the ACB and high alcohol drinking behavi

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb01001.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Mutations in nine genes have been identified in the nematode,Caenorhabditis elegans, which control sensitivity to ethanol. The interaction of these genes has been examined and used to determine a genetic pathway controlling sensitivity to ethanol. The nature of this pathway indicates that ethanol exerts its anesthetic actions at more than one site of action. These results also indicate that ethanol is similar in its effects to the volatile anesthetics, enflurane and isoflurane.

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb01002.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Expression of the class I alcohol dehydrogenase (ADH) gene in the rat hepatoma microcell hybrid cell line, 11–3, was examined. The steady‐state level of ADH mRNA in 11–3 was ∼2‐fold higher than that of rat liver and Fao, the parental cell line of 11–3. Removal of steroid hormones by activated charcoal from the serum in which 11–3 cells were maintained resulted in a significant decrease in the level of ADH transcript. Dexamethasone at a concentration of 1 μM increased the ADH mRNA content in 11–3 in a time‐dependent fashion, up to 48 hr after its addition to cells that had first been deprived of steroid hormones. In addition, levels of ADH transcript in cells treated with dexamethasone increased in a dose‐dependent manner, and the concentration of dexamethasone required to achieve half‐maximal activation was 5 nM. By using the techniques of reverse transcription and polymerase chain reaction, and by taking advantage of a restriction polymorphism present between the rat and mouse ADH cDNA, we found that 11–3 contained both the rat and mouse class I ADH transcripts, although the rat sequence accounted for the great majority. Moreover, levels of both rat and mouse class I ADH transcripts increased in a similarly time‐dependent manner in cells treated with dexamethasone. These results indicate that expression of class I ADH gene in 11–3 is high and is regulated by glucocorticoids, making the cell line an excellent model for the in v

ISSN:0145-6008    

DOI:10.1111/j.1530-0277.1995.tb01003.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY