Demonstration of a functional blood-testis barrier to acetaldehyde. Evidence for lack of acetaldehyde effect on ethanol-induced depression of testosterone in vivo

An overlooked issue: sexual dysfunctions in men addicted to alcohol

Introduction According to the data obtained in the EZOP Poland study (2015), the prevalence of alcohol dependence in lifetime in Poland amounts to about 2.2% of the population, entailing enormous social, family and personal harm, including health damage. It is estimated that about 72% of alcohol-dependent patients complain about one or more problems related to the sexual sphere, which may result from both the development of somatic complications in the course of alcohol dependence, and from psychiatric complications that themselves can lead to sexual dysfunction. There are reports and clinical observations indicating that the occurrence of sexual dysfunction (SD) can affect the shortening or interruption of the period of abstinence.

Aim The aim of this work is to show sexual dysfunctions in alcohol-dependent men and to discuss the factors that may affect the occurrence of the above-mentioned dysfunctions.

Material and methods The available literature was reviewed using Medline, Google Scholar and ScienceDirect browsers by entering the keywords: alcohol dependence, sexual dysfunction, comorbidity, alcohol-caused diseases and time descriptors: 1979-2016.

Results

• Alcohol dependence is associated with the occurrence of various types of sexual dysfunctions (SD).

• The diagnosis of SD should take into account all possible causes that may lead to the development of SD in this group of patients, including the comorbidity of somatic diseases or the negative impact of drugs on sexual function.

• Occurrence of SD is connected with a higher risk of abstinence interruption.

• There is a need to carry out more research in order to better understand the relationship between alcohol dependence and the prevalence of sexual dysfunctions.

Sexual dysfunction in patients with alcohol and opioid dependence

There are limited numbers of studies which have evaluated the sexual dysfunction (SD) in patients with alcohol and opioids dependence. This article reviews the existing literature. Electronic searches were carried out using the PubMed, Google Scholar, and ScienceDirect to locate the relevant literature. Subjects addicted to heroin or on methadone maintenance treatment (MMT) or buprenorphine maintenance treatment (BMT) show higher rates of SD in comparison to the general population. SD rates have ranged 34-85% for heroin addicts, 14-81% for MMT, 36-83% for BMT, and 90% for naltrexone maintenance. The rates of SD in alcohol-dependent population have ranged 40-95.2%, with rates being consistently much higher in alcohol-dependent population than in the healthy controls or social drinkers. The common SDs reported have been erectile dysfunction followed by premature ejaculation, retarded ejaculation and decreased sexual desire among men, and dyspareunia and vaginal dryness among women. This review suggests that long-term use of alcohol and opioids are associated with SD in almost all domains of sexual functioning. There is a need to increase the awareness of clinicians about this association as many times SD in patients with substance abuse lead to poor treatment compliance and relapse. Further, there is a need to carry out more number of studies to understand the relationship in a better way.

Effects of alcohol on the endocrine system

Chronic consumption of a large amount of alcohol disrupts the communication between nervous, endocrine, and immune system and causes hormonal disturbances that lead to profound and serious consequences at physiologic and behavioral levels. These alcohol-induced hormonal dysregulations affect the entire body and can result in various disorders such as stress abnormalities, reproductive deficits, body growth defect, thyroid problems, immune dysfunction, cancers, bone disease, and psychological and behavioral disorders. This review summarizes the findings from human and animal studies that provide consistent evidence on the various effects of alcohol abuse on the endocrine system.

Impact of the Hormonal Milieu on the Neurobiology of Alcohol Dependence and Withdrawal

Alcoholism, or alcohol dependence, is a complex disorder with withdrawal symptoms that are often problematic for those trying to recover from their dependence. As researchers attempt to elucidate the neurobiological underpinnings of alcohol dependence and withdrawal, it is becoming clear that numerous factors, including the hormonal environment, impact the manifestations of this disorder. Of particular interest is the observation that women have fewer and less severe withdrawal symptoms than do men even though they tend to suffer greater physiological harm from excessive alcohol consumption. In this article, the authors present an overview of their understanding of how gonadal and stress hormones interact with alcohol, which results in differential neurobiological responses between males and females. Thus far, data generated from representative animal models have shown significant differences between the sexes in behavioral responses and neuroadaptations to chronic alcohol consumption and withdrawal. Accumulating evidence suggests that treatment of alcoholism, including withdrawal, should be tailored to the patient's gender and hormonal status.

Dose and time dependent effects of ethanol on antioxidant system in rat testes

This study was designed to investigate the dose as well as time dependent effects of ethanol on testicular antioxidant defense system in rats. Male Fischer 344 rats were administered ethanol at a dose of 2, 4, and 6 gm/kg orally and control received equal volume of saline and sacrificed 1 h after ethanol ingestion. For time course study, animals were administered ethanol 4 g/kg orally and sacrificed at 1.5, 2, 4, and 6 h after ethanol ingestion. Testicular ethanol concentration increased with increasing doses of ethanol. Copper zinc-superoxide dismutase (CuZn-SOD) activity significantly decreased in the testes of rats treated with increasing doses of ethanol whereas manganese-superoxide dismutase (Mn-SOD) activity significantly increased in a dose dependent manner (181, 186, and 195% of control, respectively). Testicular glutathione (GSH) and malondialdehyde (MDA) levels did not significantly alter with increasing doses of ethanol one hour after ethanol ingestion. Ethanol concentration decreased in the testes with an increase in time after ethanol ingestion. Testicular CuZn-SOD activity significantly decreased whereas Mn-SOD activity increased with an increase in time after ethanol ingestion. Testicular catalase (CAT) activity significantly decreased at 2 h postethanol ingestion. Testicular MDA levels significantly increased at 4 and 6 h after ethanol ingestion indicating that end product of lipid peroxidation. MDA, takes considerable time to form in the testes. A significant decrease in the ratios of CAT/Mn-SOD and glutathione peroxidase (GSH-Px)/Mn-SOD in the testes of rat suggests the ability of mitochondria to scavenge reactive oxygen species (ROS). It is suggested that antioxidant enzyme ratios may be used as an important parameter to determine ethanol induced oxidative stress in the tissues.

Evaluation of the co-mutagenicity of ethanol and Δ9-tetrahydrocannabinol with Trenimon

The mutagenic potential of chronic treatments of male CF-1 mice with ethanol and delta 9-tetrahydrocannibinol (THC), and their comutagenic potential with a known mutagenic agent, Trenimon, were examined. This was accomplished by measuring the frequency of dominant lethal mutations arising from mating of treated males with nontreated females. Adult male mice were treated with 5% (v/v) ethanol as part of a liquid diet (28% ethanol-derived calories) for five weeks; 10 mg/kg body weight (p.o.) THC every two days for five weeks; a single injection of Trenimon (0.125 mg/kg, i.p.) on day 28 of diet treatment; and all combinations of treatments. The control group was pair-fed a liquid diet in which isocaloric sucrose replaced ethanol; these males were also given sesame oil (vehicle for THC) and saline (vehicle for Trenimon) on the same schedule as that for the treated males. Neither body weights nor hematocrits were adversely affected by any treatment. Both ethanol and Trenimon treatments resulted in a small (8-9%; p less than 0.05) decrease in testicular weight. The effect of combined treatment with ethanol and Trenimon was roughly additive. Treatment with THC had no effect on testicular weight. Seminal vesicle weights were not affected by any treatment. Treatments were without significant effect on fertility, as measured by the frequency of males producing pregnancies. Ethanol and Trenimon treatments produced approximately 3- and 7-fold increases, respectively in the frequencies of preimplantational loss over that seen for the control group (7.3%), resulting in significant ethanol and Trenimon effects (p less than 0.001). No interactive effects of ethanol and Trenimon treatments were noted. Frequencies of dead fetuses per pregnancy in the ethanol- and Trenimon-treated groups were increased approximately 2.5- and 4-fold, respectively, over the control value of approximately 16%. However, the effect of combined treatments was not greater than that due to Trenimon alone, resulting in Trenimon and ethanol effects (p less than 0.001) and ethanol-Trenimon interaction (p less than 0.001). The calculated mutation index resulting from each treatment yielded significant (p less than 0.001) ethanol- and Trenimon-induced effects. In contrast to effects of ethanol and Trenimon treatments, THC, given alone, or in combination with ethanol and/or Trenimon, had no effect on either preimplantational loss, fetal mortality or the resulting mutation index. The data suggest that chronic ethanol treatment, at levels resulting in minimal fertility impairment, increases the frequency of dominant lethal mutations. In contrast, chronic treatment with THC, as administered in the present study, appears to be without effect.(ABSTRACT TRUNCATED AT 400 WORDS)

Penetration of ethanol into the male reproductive tract

We studied the pharmacokinetics of ethanol in the rat rete testis fluid, interstitial fluid, seminiferous tubules, epididymal fluid, and whole testis after 0.75 g/kg and 1.5 g/kg intraperitoneal injections. Ethanol concentration in these tissues was compared to that in capillary and arterial blood. The data was characterized by fitting to a mathematical model. The highest ethanol concentrations in orbital capillary blood were measured 10 min after the injections. Ethanol content in testis homogenate and interstitial fluid did not generally differ from that of orbital blood. However, in rete testis fluid the highest ethanol values were measured at 60 min by the 1.5 g/kg dose and at 30 min by 0.75 g/kg. Ethanol values before this differed from those of capillary blood and interstitial fluid (p less than 0.05-0.001). In seminiferous tubules, the highest ethanol concentration was reached at 20 min, and ethanol content was in general lower than in orbital blood (p less than 0.001-0.01). Ethanol levels in epididymal fluid were comparable to capillary blood. The transportability factor from the model for rete testis was low, which indicates a barrier of penetration of ethanol from blood. In addition, water contents of testicular compartments were calculated. The area under the curve values of rete testis and seminiferous tubules were approximately 10 and 30%, respectively, smaller than that of interstitial fluid, for example. Therefore, the germ cells are somewhat better protected from ethanol than the interstitial cells.

Biochemical and structural evidence for ethanol-induced impairment of testicular development: apparent lack of Leydig cell involvement

The present study was conducted to provide biochemical and morphological evidence for ethanol-induced impairment of testicular development. The specific activities of testicular postmeiotic enzyme markers--sorbitol dehydrogenase (SDH), lactate dehydrogenase (LDH), and alpha-glycerophosphate dehydrogenase (GDH)--increased with age in CFW mice from ages 23 to 60 days, providing a biochemical measure of testicular development during puberty. Chronic ethanol treatment via liquid diets from ages 20 to 55 days resulted in decreased activities of SDH and LDH at ages 40 and 44 days, and of GDH at ages 34, 40, and 44 days. These decreases were consistent with an arrest in the developmental increase in SDH, LDH, and GDH at ages 31 +/- 0.6, 31 +/- 2.6, and 24 +/- 0.5 days, respectively. After 29 days of ethanol treatment (age 50 days), testicular weights, epididymal sperm content, and sperm motility were reduced, relative to controls, by 37, 83, and 60%, respectively (p less than 0.05). Epididymal weights were unaffected. Light microscopic evaluation of testes revealed disorganization of spermatogenesis, germ cell degeneration, decreased tubular luminal diameter, and vacuolation of Sertoli cells in ethanol-treated mice at age 50 days. Electron microscopic analysis showed that germ cell degeneration was not restricted to a specific cell type. Stage IX-XI tubules were observed in which spermatids had been retained and underwent phagocytosis within the Sertoli cell. Sertoli cells showed evidence of atypical nuclear invaginations. Sertoli cells underwent degenerative changes and were sloughed into the rete testis. However, relative Leydig cell size, as well as fractional volume occupied by the nucleus, mitochondria, and endoplasmic reticulum were unaffected by ethanol. The data (1) confirm previous findings suggesting ethanol-induced delayed testicular development; (2) suggest that certain aspects of testicular development are arrested relatively early in ethanol treatment (4-11 days); and (3) indicate that the Sertoli cell, rather than the Leydig cell, is the primary target with regard to the deleterious effect of chronic ethanol treatment on testicular maturation.

Inhibition of testosterone synthesis by ethanol: role of luteinizing hormone

The effects of acute ethanol intake (1.5 g/kg) on plasma testosterone and luteinizing hormone (LH) concentrations were examined in male Long-Evans rats. Ethanol decreased the serum LH concentrations by 21% and 42% 30 and 60 minutes after ethanol administration respectively. The testosterone concentrations decreased later (30 min: +8%; 60 min: -30%). The LH concentrations were highly correlated with subsequent (60 min later) testosterone concentrations (LH30min: r = .688, p less than 0.001, n = 25; LH60min: r = .678, p less than 0.001), but less so with concurrent testosterone concentrations (30 min: r = .187, N.S.; 60 min: r = .552, p less than 0.004). To further test the influence of LH, naloxone (11 mg/kg) was administered, which elevated the LH levels within 30 min by 103% in controls. Naloxone also increased serum LH concentration by 34% in ethanol-treated rats at 30 min, but these animals nevertheless had lower (p less than 0.01) testosterone levels at 60 min than did control animals without naloxone and ethanol treatment. It is concluded that although ethanol-induced changes in serum LH levels may play a role in the decrease of serum testosterone concentrations in rats, there are also other mechanisms by which ethanol may produce these effects.

Chronic ethanol ingestion during puberty alters the transient increase in testicular 5 alpha-reductase in the Swiss-Webster mouse

Previous experiments with inbred mice showed that chronic ethanol treatment delays male pubertal development. An initial event in sexual maturation in the rat is a transient increase in 5 alpha-reductase. The present study was conducted to determine whether similar ethanol effects occur in outbred mice (Swiss-Webster), to determine the ontological profile of testicular 5 alpha-reductase in the mouse, and to evaluate the effect of ethanol treatment on this enzyme. After 29 days of treatment with a liquid diet (beginning at age 20 days), reductions in the ethanol-treated mice as compared with the controls were noted in testicular weight (55.0 +/- 2.0 vs. 63.0 +/- 2.4 mg; P less than 0.01), epididymal sperm content (6.8 X 10(5) vs. 14.4 X 10(5); P less than 0.05), and sperm motility (45% vs. 57%; P less than 0.05). After 43 days, differences no longer existed. In chow-fed mice, a substantial rise in 5 alpha-reductase (1 unit = 1 pmole DHT formed/45 min/mg testis) began at age 24 days. Activity peaked at approximately 65 units at 25 to 30 days and gradually declined to 6.4 +/- 0.8 units at 63 days. After 29 days treatment, 5 alpha-reductase of the pair-fed control group was 26.8 +/- 4.9 units, which decreased to a baseline value of 7.0 +/- 2.1 units after 43 days treatment. In contrast, 5 alpha-reductase of the ethanol-treated group remained at baseline levels after 29 days (7.7 +/- 2.3 units) and 43 days of treatment (7.6 +/- 2.3 units).(ABSTRACT TRUNCATED AT 250 WORDS)

Ethanol-induced delayed male puberty in mice is not due to impaired Leydig cell function

The present study was performed to evaluate the involvement of reduced testosterone in ethanol-induced impairment of male reproductive tract development. In vivo and in vitro gonadotropin (hCG)-stimulated steroidogenesis were examined in CFW mice as a function of chronic ethanol treatment during pubertal development. Chronic ethanol treatment from ages 20 to 49 days impaired testicular growth from ages 35 days (29 +/- 2 mg vs 37 +/- 2 mg for pair-fed controls) to 50 days (42 +/- 2 mg vs 63 +/- 2 mg for pair-fed controls). Consistent with a reduction in testicular weight, testicular content of androstenedione, testosterone, and dihydrotestosterone (DHT) was depressed in ethanol-treated mice. At age 50 days, the content (expressed as pg/testis) of androstenedione, testosterone, and DHT was reduced in ethanol-treated animals by 49%, 31%, and 38%, respectively, as compared to that of their respective controls. However, no difference in plasma (ng/mL) or testicular (pg/mg protein) concentrations of steroids was observed. Except for the DHT response at ages 35 to 40 days, neither in vivo nor in vitro steroidogenesis was impaired by chronic ethanol treatment at ages 26 to 50 days; similarly, the acute ethanol effect on steroidogenesis was unaffected. However, an adaptive increase (54%-173%) in the in vivo testosterone response to hCG was seen at ages 26 to 40 days. The data indicate that 1) chronic ethanol treatment does not impair gonadotropin-stimulated steroidogenesis or result in tolerance to acute ethanol effects on steroidogenesis in older animals; and 2) ethanol-induced reduction in testosterone is not a likely mechanism for delayed sexual maturation.

Testosterone production by the prepubertal mouse testis is not depressed by ethanol

The purpose of the present study was to evaluate the sensitivity of testicular steroidogenesis during pubertal development to inhibition by ethanol. In vivo and in vitro human chorionic gonadotropin (hCG)-stimulated steroidogenesis were examined in CFW mice as a function of age. Plasma androstenedione, testosterone, and dihydrotestosterone (DHT) increased from ages 23 to 60 days in control mice. Acute ethanol treatment (3 g/kg) yielded static levels of androstenedione (0.45 +/- 0.03 ng/mL), testosterone (6.4 +/- 0.56 ng/mL), and DHT (2.3 +/- 0.18 ng/mL) from ages 23 to 60 days, 30 to 60 days, and 35 to 60 days, respectively, resulting in reduction of plasma androstenedione, testosterone, and DHT (P less than 0.05) relative to control values, but not until ages 35, 50, and 45 days, respectively. A similar insensitivity of the prepubertal testis to ethanol was seen in vitro. Inhibition of in vitro androstenedione and testosterone accumulation was seen only after ages 26 and 45 days, respectively. The data indicate that testosterone production by the pubertal testis is relatively insensitive to direct inhibition by ethanol. Previous studies have shown that chronic ethanol treatment of adolescent mice delays testicular maturation. The present study suggests that if chronic ethanol-induced delayed testicular development were due to impaired steroidogenesis, such impairment would be secondary to reduced gonadotropin stimulation and/or due to a chronic, rather than an acute, effect of ethanol.

International Commission for Protection against Environmental Mutagens and Carcinogens. ICPEMC Working Paper No. 15/5. Acute aldehyde syndrome and chronic aldehydism

Different types of alcohol dehydrogenase and of aldehyde dehydrogenase lead to different blood acetaldehyde levels. With respect to acetaldehyde levels in human blood 3 types can be distinguished: (1) the normal range, (2) the acute aldehyde syndrome, and (3) the chronic aldehydism. Acetaldehyde is electrophilic and reacts with nucleophilic groups of various macromolecules including DNA. Acetyldehyde inhibits synthetic and metabolic pathways, it interferes with the polymerization of tubulin and stimulates collagen synthesis. By depletion of cellular glutathione levels, acetaldehyde leads to lipid peroxidation and to the formation of malonaldehyde. There are indications that acetaldehyde may play a role in positively reinforcing mood changes induced by alcohol in humans.

Concomitant mutagenicity of ethanol and x-ray irradiation in the mouse male germ cells

The mutagenic effect of ethanol and x-ray irradiation on the male germ cells was investigated in the mouse. The meiotic micronuclei in the testis were recorded and the abnormalities in the epididymal sperm heads were counted. The number of micronuclei in early spermatids did not differ in the ethanol-exposed groups from that of their control groups at the end of 5 week ethanol diets. However, in the mice irradiated with a dose of 0.5 Gy, there was a statistically significant (p less than 0.01) difference in micronucleus induction between the groups of different ethanol exposure levels. No statistically significant differences were found in the numbers of abnormal sperm heads immediately after the diet or 25 days, 5 weeks and 10 weeks after the cessation of the diet. However, sperm abnormality frequencies were elevated at 5 weeks after 4 and 6% (v/v) ethanol diets and at 25 days after the 6% diet. The results suggest that ethanol is co-mutagenic with x-rays in the mouse male germ cells. Ethanol alone showed also a tendency to be mutagenic in the sperm abnormality test. The stage and mechanism of action of ethanol is discussed.

Delayed pubertal development of the male reproductive tract associated with chronic ethanol ingestion

Little is known concerning the sensitivity of the reproductive tract to ethanol as a function of development. The present study was conducted to evaluate the action of chronic ethanol ingestion on sexual maturation of the male. Mice were given free access to liquid diets containing 5% (v/v) ethanol for either 29 or 43 days, starting at age 20 days. Controls were given liquid diets in which isocaloric sucrose replaced the ethanol. Daily diet consumption and peak blood ethanol levels were highest during the first 2 weeks of treatment, dropping thereafter to adult levels of approximately 680 ml/kg body weight and 160 mg/dl respectively. Plasma testosterone levels were depressed by ethanol throughout treatment, the reduction being somewhat greater when measured during week 6 of treatment (average = 74% inhibition) as compared to either week 2 (36%) or week 4 (25%). Average weights of testes, epididymides and seminal vesicles were depressed by 24% (P less than 0.002), 16% (P less than 0.005) and 13% (NS), respectively, after 29 days. Testicular development was also impaired in ethanol-treated animals after 29 days. Tunica albuginea thickness and seminiferous tubule diameter were decreased (by 31%, P less than 0.05; and 16%, P less than 0.01 respectively), whereas desquamation of immature germ cells and inactive tubules were increased (325 and 780% respectively; P less than 0.01). Quality of spermatogenesis was poorer in ethanol-treated animals (P less than 0.05). Also observed were decreased sperm motility (62% inhibition, P less than 0.01) and capacity to fertilize (decreased by 67%, P less than 0.01), and an increase in the incidence of morphologically abnormal spermatozoa (by 163%, P less than 0.001). Semen volume was lower (reduced by 57%, P = 0.05), as was the total number of motile ejaculated spermatozoa (reduced by 81%, P less than 0.05). After 43 days treatment, improvement was noted in all indices of fertility except for the number of motile ejaculated spermatozoa. Significant differences persisted only for dysmorphic spermatozoa and volume and sperm count of electroejaculated semen. These data suggest that ethanol ingestion during pubertal development can delay several aspects of sexual maturation in the male.

Microsomal ethanol-oxidizing system in purified rat Leydig cells

These studies provide evidence for the presence of a microsomal ethanol oxidizing system in rat Leydig cells. Activity of the microsomal ethanol oxidizing system in Leydig cells was 47.4 +/- 4.1 nmol acetaldehyde per 20 min per mg protein, while activity in crude interstitial cells was 26.0 +/- 5.4 nmol. This suggests that among cells comprising interstitial cells, activity is concentrated in Leydig cells. Activity was linear with respect to protein concentration and incubation time. The highest specific activity was observed in the microsomal fraction. The most effective cofactor was NADPH. The apparent Km for ethanol was 4 mM, suggesting that this system could effectively metabolize ethanol at concentrations found in the blood of males who drink. The apparent Km for NADPH was 11 microM. The activity in Leydig cells was unaffected by 4-methylpyrazole or potassium cyanide, which inhibit alcohol dehydrogenase and catalase activities, respectively. These data provide strong evidence for an enzyme system in Leydig cell microsomes which is capable of metabolizing ethanol.

Exposure to ethanol during capacitation impairs the fertilizing ability of human spermatozoa in vitro

To validate earlier findings, mainly in laboratory animals, the effect of ethanol on the fertilizing ability of human spermatozoa has been investigated. Ethanol added to the capacitation medium reduced the penetration of zona-free hamster eggs by human spermatozoa in a dose-dependent manner at concentrations from 50 to 500 mg % (0.05-0.5%). Fertilizing capacity was at least partially restored by washing in ethanol-free medium. Ethanol exposure before capacitation had a slight stimulatory effect on the penetration of spermatozoa into zona-free hamster ova. The motility of spermatozoa was not altered significantly, either quantitatively or qualitatively, by the presence of ethanol in the capacitation medium. These results suggest that the decrease in fertilizing ability of spermatozoa induced by ethanol during capacitation is due to a specific action on the capacitation process.

Effects of ethanol on steroid profiles in the rat testis

The effects of ethanol on the concentrations of steroids in testis was studied in adult rats. Testosterone, seven of its potential precursors, three of its metabolites, and estradiol were analyzed by gas chromatography-mass spectrometry of samples from testes removed 2 h after intraperitoneal administration of ethanol, 1.2 g/kg body weight. The same analyses were made on samples from control rats. Ethanol gave a marked increase of all 3 beta-hydroxy-delta 5 steroids analyzed: pregnenolone (60%), 17-hydroxypregnenolone (480%), dehydroepiandrosterone (430%) and 5-androstene-3 beta, 17 beta-diol (60%). This resulted in highly significant increases of the 3 beta-hydroxy-delta 5/3-oxo-delta 4 steroid ratios for all steroid couples analyzed. An analogous increase of the ratio between 5 alpha-androstane-3 beta, 17 beta-diol and dihydrotestosterone was also observed, whereas the ratio between androstenediol and dehydroepiandrosterone was decreased by ethanol. The concentration of estradiol was not affected. The results indicate that moderate doses of ethanol inhibit the conversion of 3 beta-hydroxy-delta 5 to 3-oxo-delta 4 steroids. This may be one mechanism by which ethanol decreases the production of testosterone.

Partial characterization of alcohol dehydrogenase activity in purified rat Leydig cells

Ethanol metabolism to acetaldehyde by NAD+-dependent alcohol dehydrogenase (ADH) activity reduces, in part, androgen secretion by rat Leydig cells. ADH in Leydig cells is proposed to decrease the NAD+/NADH ratio and thereby inhibit NAD+-dependent delta 5-3 beta hydroxysteroid dehydrogenase-isomerase activity and increase NADH-dependent 5 alpha-androstane-3 beta-hydroxysteroid dehydrogenase activity. Although the reciprocal changes in these steroidogenic enzyme activities by ethanol are attributed to ADH activity, there is very little information about this enzyme in purified Leydig cells. The present studies examined specific characteristics of this enzyme in metrizamide-gradient purified Leydig cells. ADH activity was linear with respect to protein concentration and incubation time. The activity was concentrated in the soluble fraction, and the most effective cofactor was NAD+. The apparent Km for ethanol was 0.50 mM, and the Vmax was 53 nmol NADH/10 min/mg protein. When Leydig cell cytosol was incubated with a fixed ethanol concentration (50 mM) and increasing NAD+ and the data were plotted according to Lineweaver-Burk, a biphasic curve was observed with apparent Km's of 0.032 and 0.17 mM. The optimum pH for the enzyme was 8.2, and the enzyme was inhibited in a dose-dependent manner by 4-methylpyrazole. These studies further characterize ADH activity in purified Leydig cells and demonstrate that this enzyme exhibits many characteristics similar to the more widely studied liver enzyme(s).(ABSTRACT TRUNCATED AT 250 WORDS)