One injection of estradiol valerate induces dramatic changes in rats' intake of alcoholic beverages

A series of experiments investigated the effects of a single injection of estradiol valerate (EV) on female rats' consumption of alcoholic beverages. EV provides sustained release of estradiol. Just after an injection of EV, rats' intake of a palatable alcoholic beverage, which had been taken regularly before, is reduced dramatically. Subsequently, rats' intake of alcoholic beverage returns to baseline levels. With continued opportunity to drink, rats take more ethanol than controls. When EV was given 15 and 31 days before the first opportunity to drink an alcoholic beverage, female rats markedly enhanced their intake of ethanol. Once enhanced intakes emerged, they were observed with different kinds of alcoholic beverages and endured for months.     

Estradiol valerate and intake of sweetened water

Recently, it has been shown that female rats receiving very large doses (e.g., 2 mg) of estradiol valerate (EV) take considerably more alcoholic beverage than placebo controls. The question asked, with these procedures, is whether the enhanced appetite for alcoholic beverages was specific to those beverages or was a reflection of a general increase in appetite. Female rats were provided with various sweetened beverages. In one experiment, they were provided a palatable saccharin solution (0.25% solution) and a less palatable one (2% saccharin solution). EV treatment led to more intake of the palatable saccharin solution and reduced intake of the less palatable solution. EV induces changes leading to enhanced appetite for some ingesta (including palatable saccharin solutions and alcoholic beverages), but surely not all ingesta.     

Estradiol valerate and alcohol intake: dose-response assessments

Background

An injection of estradiol valerate (EV) provides estradiol for a prolonged period. Recent research indicates that a single 2.0 mg injection of EV modifies a female rat's appetite for alcoholic beverages. This research extends the initial research by assessing 8 doses of EV (from.001 to 2.0 mg/female rat), as well assessing the effects of 2.0 mg EV in females with ovariectomies.

Results

With the administration of EV, there was a dose-related loss of bodyweight reaching the maximum loss, when it occurred, at about 4 days after injections. Subsequently, rats returned to gaining weight regularly. Of the doses tested, only the 2.0 mg dose produced a consistent increase in intake of ethanol during the time previous research indicated that the rats would show enhanced intakes. There was, however, a dose-related trend for smaller doses to enhance intakes. Rats with ovariectomies showed a similar pattern of effects, to intact rats, with the 2 mg dose. After extensive histories of intake of alcohol, both placebo and EV-treated females had estradiol levels below the average measured in females without a history of alcohol-intake.

Conclusion

The data support the conclusion that pharmacological doses of estradiol can produce enduring changes that are manifest as an enhanced appetite for alcoholic beverages. The effect can occur among females without ovaries.     

Exposure-dependent effects of ethanol on serum estradiol and uterus mass in sexually mature oophorectomized rats: a model for bilaterally ovariectomized-postmenopausal women

Factors that may affect the estrogenization of postmenopausal women are important because estrogen levels may modulate the risk of osteoporosis and cardiovascular disease in postmenopausal women. Ethanol, a potential estrogenization factor, has received scant attention, particularly in postmenopausal women who are moderate users of alcoholic beverages. Because as many as 22.6% of postmenopausal women are reported to have had a bilateral oophorectomy, mature oophorectomized rats were used as a model. Low to moderate ethanol consumption was approximated by administering graded doses of ethanol in drinking water (0, 1.8, 3.7 or 5.5% ethanol, v/v) to 90 oophorectomized rats for 4 or 10 weeks. In rats exposed for 4 weeks, neither estradiol levels nor uterus weight differed among the four groups. In contrast, among rats exposed for 10 weeks, there was a significant positive correlation between ethanol dose and both uterus weight and estradiol; analysis of variance demonstrated that inclusion of the data obtained from rats receiving the 5.5% ethanol dose accounted for the significance of these associations. Based on these findings, it is suggested that, at least in oophorectomized rats, prolonged exposure to moderate ethanol doses is required to induce sufficient aromatization of androgens to produce detectable changes in plasma estradiol or in uterus weight. Further studies will be required to determine whether low or moderate alcoholic beverage use by postmenopausal women may result in biologically relevant increases in serum estradiol.     

Absence of a differential induction of cytochrome P450 2E1 by different alcoholic beverages in rats: implications for the aetiology of human oesophageal cancer

Alcohol is an important risk factor for human oesophageal cancer. There is evidence from epidemiological studies that some specific alcoholic drinks, e.g. Calvados apple brandy, are associated with a greater risk than others. Alcohol induces cytochrome P450 2E1 (CYP2E1) and the hypothesis was tested that different alcoholic beverages, containing a variety of alcoholic compounds, could differentially induce expression of cytochrome P450 enzymes. Twelve groups of five rats each were treated for 3 days with different alcoholic beverages (ethanol alone, whisky, farm-produced or commercial Calvados brandy, beer, cider, wine) adjusted to 4, 10 or 20% of ethanol in drinking water. Immunoblotting using a monoclonal antibody specific for rat CYP2E1 revealed a single protein band in liver microsomes. Densitometric quantitation of microsomal proteins demonstrated a significant two-, three- and sixfold increase in band intensity after treatment with ethanol concentrations of 4, 10 and 20% respectively, compared to control rats drinking water alone. There was a dose-dependent increase in liver microsomal metabolism of CYP2E1 substrates (para-nitrophenol and dimethylnitrosamine) in ethanol-treated rats. However, there were no significant differences in the level of CYP2E1 protein or enzymatic activity between the different alcoholic beverages at the same ethanol concentration. There was a slight increase in hepatic CYP1A-related enzymatic activities in the alcohol-treated rats compared to the controls, but no difference between the treated groups either with dose of ethanol or type of beverage. These data show that induction of CYP2E1 with acute alcohol treatment is predominantly determined by the ethanol content of the beverage. Received: 10 February 1997 / Accepted: 26 May 1997     

Amlodipine, a calcium channel inhibitor, and cocaine and ethanol's reinforcing effects.

The effects of amlodipine (from 0.1 to 3.0 mg/kg) on rats' pressing for rewarding brain stimulation, with and without cocaine administration, were assessed. None of the doses reliably modified the effects of cocaine. Also, amlodipine was given to two groups of rats taking alcohol: one group that was regularly taking a sweetened alcoholic beverage and the other taking an unsweetened alcoholic beverage. The only discernible effects of amlodipine on alcohol intake were associated with the highest dose and only with rats taking the sweetened beverage. The effects of this high dose could easily be attributable to behavioral toxicity elicited by the dose. In contrast, and confirming previous work, isradipine, another calcium channel inhibitor, produced reliable reductions on both cocaine's and alcohol's reinforcing effects. Despite the similarity of isradipine and amlodipine, isradipine apparently has some unique features with respect to cocaine and alcohol.     

Effects of sweetened ethanol solutions on ethanol self-administration and blood ethanol levels

The enhancement of voluntary self-administration of ethanol by sucrose or saccharin was tested in conjunction with measurements of blood ethanol levels. Adult male rats were given access to both tap water and one of five solutions: 0.125% saccharin, 10% sucrose, ethanol, saccharin+ethanol, or sucrose+ethanol. The rats receiving the sucrose+ethanol solution drank consistently more ethanol (>5 g/kg/day) than did the rats receiving the saccharin+ethanol solution (<3 g/kg/day) or ethanol only (<2 g/kg/day). Both sweetened solutions produced higher ethanol consumption during these periods than ethanol alone. However, no significant differences in blood ethanol levels were found between the sucrose+ethanol and saccharin+ethanol conditions, when tested at different intervals on Day 44 or Day 45 of ethanol consumption. Following 45 days of consumption, no change in the bicuculline seizure threshold was observed in the ethanol-consuming rats compared to the controls. In a separate study using 90 naive rats, rats were gavaged with ethanol (1, 2, or 3 g/kg) containing either 10% sucrose (n=10 for each dose of ethanol), 0.125% saccharin (n=10 for each dose of ethanol), or ethanol alone (n=10 for each dose of ethanol), and blood was collected from the tip of the tail 30, 60, 180, 300, and 540 min later and analyzed for ethanol concentrations. Sucrose significantly decreased the resultant blood ethanol levels at several time points following gavage. These results indicate that sucrose can significantly alter blood ethanol levels and that chronic self-administration of a sweetened ethanol solution for 6 weeks does not produce ethanol dependence.     

Beverage preference, beverage type and subject gender as determinants of alcohol consumption in the laboratory

Effects of beverage preference, beverage type and subject gender on ad libitum consumption of alcoholic beverages in the laboratory were evaluated. Undergraduate social drinkers (18 male, 18 female), with equal numbers of each gender stating a preference for beer, wine or mixed drinks, were selected. Subjects participated in three separate 30-minute ad lib drinking sessions and were presented with one of the three types of alcoholic beverage at each session. Data on total volume of beverage and of absolute ethanol consumed as well as blood alcohol concentration (BAC) attained were collected in each session. Subjects preferring wine or mixed drinks drank more alcohol and reached higher BACs when imbibing their beverage of choice than when drinking non-preferred beverages. Subjects preferring beer, however, showed no differences on these drinking measures as a function of beverage type. Men's reports of routine alcohol use had a high positive correlation with actual alcohol consumption observed in the laboratory, whereas for female subjects the correlation was near zero. Implications for interpretation of past ad lib drinking studies and the planning of future ones are discussed.     

The Canadian alcopop tragedy should trigger evidence‐informed revisions of federal alcohol regulations

On 1 March 2018, a 14‐year‐old girl was found lifeless in a stream behind her high school after having consumed FCKDUP—a beverage containing 11.9% alcohol and sold in 568 mL cans—during her lunch hour. Following her death, the Canadian government took actions at ministerial and parliamentary levels by seeking experts’ advice to better regulate highly sweetened alcoholic beverages, otherwise referred to as ‘alcopops’. We suggest that the Canadian government uses the work surrounding the alcopop tragedy as an opportunity to make significant amendments and revisions of federal alcohol regulations.     

A single sip of a strong alcoholic beverage causes exposure to carcinogenic concentrations of acetaldehyde in the oral cavity

The aim of this study was to explore oral exposure to carcinogenic (group 1) acetaldehyde after single sips of strong alcoholic beverages containing no or high concentrations of acetaldehyde.Eight volunteers tasted 5 ml of ethanol diluted to 40 vol.% with no acetaldehyde and 40 vol.% calvados containing 2400 μM acetaldehyde. Salivary acetaldehyde and ethanol concentrations were measured by gas chromatography. The protocol was repeated after ingestion of ethanol (0.5 g/kg body weight).Salivary acetaldehyde concentration was significantly higher after sipping calvados than after sipping ethanol at 30 s both with (215 vs. 128 μmol/l, p < 0.05) and without (258 vs. 89 μmol/l, p < 0.05) alcohol ingestion. From 2 min onwards there were no significant differences in the decreasing salivary acetaldehyde concentration, which remained above the level of carcinogenicity still at 10 min. The systemic alcohol distribution from blood to saliva had no additional effect on salivary acetaldehyde after sipping of the alcoholic beverages.Carcinogenic concentrations of acetaldehyde are produced from ethanol in the oral cavity instantly after a small sip of strong alcoholic beverage, and the exposure continues for at least 10 min. Acetaldehyde present in the beverage has a short-term effect on total acetaldehyde exposure.     

Acetaminophen hepatotoxicity precipitated by short-term treatment of rats with ethanol and isopentanol: protection by triacetyloleandomycin

Ethanol and isopentanol are the predominant alcohols in alcoholic beverages. We have reported previously that pretreatment of rats with a liquid diet containing 6.3% ethanol plus 0.5% isopentanol for 7 days results in a synergistic increase in acetaminophen hepatotoxicity, compared with rats treated with either alcohol alone. Here, we investigated the role of CYP3A in acetaminophen hepatotoxicity associated with the combined alcohol treatment. Triacetyloleandomycin, a specific inhibitor of CYP3A, protected rats pretreated with ethanol along with isopentanol from acetaminophen hepatotoxicity. At both 0.25 and 0.5 g acetaminophen/kg, triacetyloleandomycin partially prevented elevations in serum levels of alanine aminotransferase. At 0.25 g acetaminophen/kg, triacetyloleandomycin completely protected 6 of 8 rats from histologically observed liver damage, and partially protected the remaining 2 rats. At 0.5 g acetaminophen/kg, triacetyloleandomycin decreased histologically observed liver damage in 7 of 15 rats. In rats pretreated with ethanol plus isopentanol, CYP3A, measured immunohistochemically, was decreased by acetaminophen treatment. This effect was prevented by triacetyloleandomycin. These results suggest that CYP3A has a major role in acetaminophen hepatotoxicity in animals administered the combined alcohol treatment. We also found that exposure to ethanol along with 0.1% isopentanol for only 3 days resulted in maximal increases in acetaminophen hepatotoxicity by the combined alcohol treatment, suggesting that short-term consumption of alcoholic beverages rich in isopentanol may be a risk for developing liver damage from acetaminophen.     

Protracted withdrawal: sensitization of the anxiogenic response to cocaine in rats concurrently treated with ethanol.

Rats were trained to respond on one lever following an injection of saline and the alternate lever after the anxiogenic drug pentylenetetrazol (PTZ 20 mg/kg), according to a fixed ratio (FR10) schedule of food reinforcement. The trained animals were then administered dependence-producing regimens of either cocaine (20 mg/kg, [IP], three times daily for 7 days) or ethanol (mixed 4.5% w/v with sweetened liquid diet given for 5 days). Separate groups of trained rats were given either subthreshold regimens of cocaine (20 mg/kg, IP, three times daily for 5 days), ethanol (2.25% w/v of the diet given for 5 days), or both. Additional groups were matched for control groups. After discontinuation of these regimens, rats were administered test injections of either saline or cocaine, and tested for elicitation of the PTZ-stimulus at selected intervals of withdrawal. After a saline injection, maximum elicitation of the PTZ-stimulus was observed 12 hours following chronic treatment with the higher dose of ethanol, and 120 hours following longer treatment with cocaine. During those periods of withdrawal when a saline injection failed to produce a PTZ-like stimulus, a test injection of cocaine (10 mg/kg) elicited the PTZ-stimulus in the ethanol withdrawn rats, although only partially eliciting the PTZ-stimulus in the cocaine withdrawn group. In the pair-fed controls, or rats withdrawn from the smaller dosage of either ethanol or cocaine, the test dose of saline or cocaine did not elicit the PTZ-stimulus; only 30% of rats selected the PTZ-appropriate level at the highest dose of cocaine tested (10 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Agreement between two dietary methods in reported intake of beer, wine and liquor

This study compares reported beer, wine and liquor intake from a dietary quantity-frequency questionnaire and a 16-day diet diary kept by the same respondents in the 1984-85 University of Michigan Food Frequency Study. The study subjects were 228 black and white men and women, aged 24-51 years. On the two methods, the reported mean ethanol intake derived from each beverage, mean frequency of intake of each beverage and mean quantity for each beverage were similar. The relative rankings of individuals by the amount of ethanol for each beverage were also similar. The methods agreed less well on whether a particular beverage was ever consumed. The absolute amount of ethanol from each beverage agreed more closely between methods than did the percent of ethanol from each beverage. Results were similar for each race-sex subgroup. These findings suggest that analyses should use the reported amount of ethanol from each beverage, rather than converting to percentages or classifying according to the most used beverage. The good general agreement in the types and amounts of alcoholic beverages reported promotes some confidence in the relative validity of data from these two dietary methods for describing moderate alcohol intake in the general population.     

The role of acetaldehyde outside ethanol metabolism in the carcinogenicity of alcoholic beverages: Evidence from a large chemical survey

Acetaldehyde is a volatile compound naturally found in alcoholic beverages, and it is regarded as possibly being carcinogenic to humans (IARC Group 2B). Acetaldehyde formed during ethanol metabolism is generally considered as a source of carcinogenicity in alcoholic beverages. However, no systematic data is available about its occurrence in alcoholic beverages and the carcinogenic potential of human exposure to this directly ingested form of acetaldehyde outside ethanol metabolism. In this study, we have analysed and evaluated a large sample collective of different alcoholic beverages (n=1,555). Beer (9+/-7 mg/l, range 0-63 mg/l) had significantly lower acetaldehyde contents than wine (34+/-34 mg/l, range 0-211 mg/l), or spirits (66+/-101 mg/l, range 0-1,159 mg/l). The highest acetaldehyde concentrations were generally found in fortified wines (118+/-120 mg/l, range 12-800 mg/l). Assuming an equal distribution between the beverage and saliva, the residual acetaldehyde concentrations in the saliva after swallowing could be on average 195 microM for beer, 734 microM for wine, 1,387 microM for spirits, or 2,417 microM for fortified wine, which are above levels previously regarded as potentially carcinogenic. Further research is needed to confirm the carcinogenic potential of directly ingested acetaldehyde. Until then, some possible preliminary interventions include the reduction of acetaldehyde in the beverages by improvement in production technology or the use of acetaldehyde binding additives. A re-evaluation of the 'generally recognized as safe' status of acetaldehyde is also required, which does not appear to be in agreement with its toxicity and carcinogenicity.     

Increased ethanol choice in social drinkers following ethanol preload

This study showed that normal social drinkers were more likely to consume ethanol after receiving a "priming" (preload) dose of ethanol. Twenty-eight non-problem drinkers (average consumption 9 drinks/week) participated in a six-session, double-blind choice procedure. On the first two sessions they sampled beverages containing ethanol (0.8g/kg) or placebo (mix alone), between which they would choose on subsequent choice sessions. On the third session ("dummy" choice session) subjects were first asked to indicate verbally which beverage they preferred. If they chose the ethanol-containing beverage the experimenter negotiated with each subject to determine the minimum amount of money (from $1 to $30) needed to switch his or her choice from ethanol to placebo. Once this amount was determined it remained fixed for the subsequent three preload/choice sessions. Thus, on choice sessions subjects chose between the beverage which contained ethanol, and placebo plus the amount of money established in Session 3. On the preload/choice test sessions (Sessions 4-6) subjects received preloads of ethanol (0, 0.25 or 0.5g/kg) 1h before being given the choice between the sampled ethanol beverage and the placebo beverage plus money. The frequency of ethanol choice was the primary dependent variable. Subjective drug effects, including ratings of desire for the sampled substances, were also measured. Twenty subjects initially chose ethanol on Session 3 and switched their choice with a monetary incentive. Of these 20 subjects, four chose ethanol after the placebo preload, seven chose ethanol after the low-dose ethanol preload, and 11 chose ethanol after the higher ethanol preload (significant linear trend, Mantel-Haenszel test, p < 0.03). Ratings of desire for the ethanol-containing beverage increased after the higher preload. These results suggest that ingestion of a moderate dose of ethanol increases the tendency to continue drinking, even among normal social drinkers.     

Alcoholic beverages as a source of estrogens

Alcoholic beverages contain not only alcohol but also numerous other substances (i.e., congeners) that may contribute to the beverages' physiological effects. Plants used to produce alcoholic beverages contain estrogenlike substances (i.e., phytoestrogens). Observations that men with alcoholic cirrhosis often show testicular failure and symptoms of feminization have suggested that alcoholic beverages may contain biologically active phytoestrogens as congeners. Biochemical analyses have identified several phytoestrogens in the congeners of bourbon, beer, and wine. Studies using subjects who produced no estrogen themselves (i.e., rats whose ovaries had been removed and postmenopausal women) demonstrated that phytoestrogens in alcoholic beverage congeners exerted estrogenlike effects in both animals and humans. Those effects were observed even at moderate drinking levels.     

Induction of zinc-thionein by estradiol and protective effects on inorganic mercury-induced renal toxicity

The castrated or unoperated male rats received an intravenous injection of HgCl2 at a dose of 0.7 mg/kg of body weight (b.w.) after pretreatment with 30% ethanol or estradiol dissolved in 30% ethanol at a dose of 0.5 mg/kg b.w. subcutaneously twice a day for six consecutive days. Renal total protein, gamma-GTP and K excretion in the rats treated with Hg and estradiol were significantly lower than the corresponding values in the rats treated with Hg alone, suggesting that pretreatment with estradiol ameliorates the renal toxicity of Hg in male rats. Pretreatment with estradiol significantly increased Hg and Hg-thionein(Hg-MT) concentrations in the renal cortex of the animals treated with Hg, though in the liver this agent did increase the Hg-MT without elevation of Hg concentration. Treatment with estradiol alone (0.5 mg/kg, s.c., twice a day, for six consecutive days) significantly increased the zinc-thionein (Zn-MT) concentration in the kidney and liver. Simultaneous treatment with 10(-5) M estradiol and Hg in human amniotic-fluid cells caused a significant increase in the uptake of Hg and the synthesis of Hg-MT, suggesting that estradiol may directly stimulate an accumulation of Hg into the cells and the synthesis of Hg-MT. Together, all of the above findings suggest that pretreatment with estradiol may increase the uptake of Hg, which in turn leads to the increase in the Hg-MT concentration. The induction of Zn-MT by pretreatment with estradiol may account for the protective effect of estradiol on Hg-induced renal toxicity.     

Glycine prevents hepatic fibrosis by preventing the accumulation of collagen in rats with alcoholic liver injury

We studied the effect of administering glycine, a non-essential amino acid, on liver collagen content and its characteristics in experimental hepatotoxic Wistar rats. All the rats were fed standard pellet diet. Hepatotoxicity was induced by orally administering ethanol (7.9 g kg(-1)) for 30 days. Control rats were given isocaloric glucose solution. Glycine was administered subsequently at a dose of 0.6 g kg(-1) po every day, along with alcohol for the next 30 days. Alcohol administration significantly elevated the levels of liver hydroxyproline and total collagen content, cross-linked fluorescence, shrinkage temperature and lipid peroxidation, whereas it significantly decreased the solubility of liver collagen as compared with the control rats. Simultaneous glycine supplementation to alcohol-fed rats significantly reduced the levels of liver hydroxyproline and total collagen content, cross-linked fluorescence, shrinkage temperature and lipid peroxidation and enhanced the solubility of liver collagen as compared with the unsupplemented alcohol-fed rats. In conclusion, administration of glycine had a positive influence both on the quantitative and qualitative properties of hepatic collagen in alcoholic liver injury.     

Behavioral responses to ethanol in light and moderate social drinkers following naltrexone pretreatment

The opioid antagonist naltrexone has been shown to be effective in the treatment of alcoholism, possibly by dampening the subjective effects of ethanol. However, naltrexone does not consistently attenuate the effects of ethanol in social drinkers in laboratory-based challenge studies. In the present study, 25 healthy volunteers, who were either light drinkers (mean=3 drinks per week) or moderate drinkers (mean=16 drinks per week), participated in six evening sessions. At each session, subjects ingested a capsule containing naltrexone (25 or 50 mg) or placebo, and 1 hr later they consumed a beverage containing ethanol (0.25 g/kg, equivalent to about two standard alcoholic drinks) or placebo. Subjects received all combinations of pretreatments and beverages. They completed self-report mood questionnaires and psychomotor tests at regular intervals. This low dose of ethanol produced modest but significant effects on self-report measures such as ratings of feeling a drug effect and of liking the drug effect. However, naltrexone (25 or 50 mg) pretreatment had no dampening effect on subjects' responses to ethanol. These results indicate that acute doses of naltrexone that are effective when administered chronically to alcoholics do not attenuate the acute effects of a low dose of ethanol in non-problem drinkers.     

Factors related to problem-drinking rates

Intercorrelation and regression analyses of data obtained from a drinking-related behavior and attitude household survey (N = 1127) of adults (age 18+) in Iowa are reported. The consumption variables were based on the 30 days prior to interview and included total ounces of absolute alcohol consumed; number of days the subject drank beer, wine and distilled spirits separately; typical quantity of each beverage consumed on drinking days; and the number of days drank five or more drinks within a couple of hours. The drinking attitude variables included level of tolerance (approve, indifferent, disapprove) of others' (men, women, spouse, son and daughter) drinking, getting high and getting intoxicated; a balance score of the proportion of positive and negative definitions of alcoholic beverages endorsed; an level of concern (not worried, somewhat worried and very worried) for eight possible consequences of heavy drinking. The drinking context variables used were the number of past 30 days that respondents drank at a bar or tavern, restaurant or club, home, others' homes, sports event and outdoor recreation; and number past 30 days drank alone, with relatives, work associates and close friends who are not work associates. The family environment variables included the respondent's report of whether any blood-related relatives had experienced alcohol-related problems, and of whether beverage alcohol was used in their childhood home.(ABSTRACT TRUNCATED AT 250 WORDS)