Alcohol and its effect on endocrine functioning

Failure of ethanol to induce changes in gonadotropin gene expression in selectively bred ethanol-sensitive rats

The recent availability of genetically altered rat lines differing in sensitivity to ethanol (EtOH) has allowed deeper investigation into the mechanisms of EtOH-induced cellular toxicity in several systems. Since the male central reproductive axis has been demonstrated to be exquisitely sensitive to EtOH, studies were undertaken to determine if the gonadotropin suppression reported earlier could be duplicated in one of these selected rat lines. Castrated high alcohol sensitivity (HAS), low alcohol sensitivity (LAS) and control alcohol sensitivity (CAS) rats were given EtOH or saline acutely. Castrated non-selectively bred Sprague Dawley rats were treated similarly and used as an additional control. At sacrifice, serum and pituitary luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were obtained and the mRNA levels for both gonadotropins assessed. In the selectivity bred animal there was essentially no change in serum or pituitary LH or FSH levels between EtOH and saline treated animals. The mRNA levels for both LH and FSH similarly were unaffected by EtOH, in striking contrast to the non-selectively bred Sprague Dawley rats where serum LH, FSH and beta-LH mRNA levels are markedly suppressed after EtOH exposure. The selectively bred lines of rats genetically manipulated for high or low EtOH sensitivity, as well as their non-selected controls, appeared to have a hypothalamic-pituitary reproductive unit that is resistant to EtOH. This is in contrast to Sprague-Dawley rats, where suppression of this axis previously has been consistently demonstrated.

Hypothalamic-pituitary function during alcohol exposure and withdrawal and cocaine exposure

This chapter examines the neuroendocrine effects of acute exposure to and withdrawal from alcohol and cocaine, with special emphasis on the hypothalamic-pituitary-adrenal (HPA) axis. We present the results from two preliminary controlled inpatient studies that document HPA dysfunction during acute exposure to alcohol and cocaine and during withdrawal from alcohol. We discuss the methodological approach of these studies in comparison to related attempts in the literature to use measures of thyroid and prolactin regulation to predict risk of relapse to alcohol and cocaine use, respectively. Our data and the results of related studies are presented in the context of a proposed index of HPA axis dysfunction that may provide a useful clinical measure of susceptibility to relapse during protracted abstinence from alcohol or cocaine.

Menstrual disturbances and fertility in chronic alcoholic women

Data on menstrual pattern, gynecological disorders and infertility were obtained from 51 chronic alcoholic women aged 20--42 years attending an outpatient clinic for alcoholics, using 51 randomly drawn age-matched healthy women as controls. A higher variability (P less than 0.05) in the duration of both menstrual cycle and menstrual flow was recorded in the chronic alcoholic women during active alcoholism. A higher frequency (P less than 0.05) of menstrual disturbances (70% vs. 55%) and uterine curettages (38% vs. 16%) were found in the alcoholic women. The latter reported more abortions (63% vs. 28%, P less than 0.001) and miscarriages (23% vs. 8%, P less than 0.05) than controls, but due to a higher number of pregnancies in the alcoholic group the proportion of abortions and miscarriages did not differ significantly. No differences existed between the groups regarding frequency of difficult conception. Social classification had no independent influence on the results. The study shows that chronic alcoholic women are more prone to menstrual abnormalities and are at greater risk of gynecological interventions, while they do not seem to have reduced fertility.

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.

Alcohol-induced changes in pituitary-adrenal activity during pregnancy

This study examined the interactive effects of ethanol and nutritional status on pituitary-adrenal function of pregnant females consuming high doses of ethanol throughout gestation. Three liquid diets were formulated ranging in protein content from suboptimal to supraoptimal (18%, 25%, or 32% of total calories) in terms of pregnancy requirements, while ethanol was held constant at high levels (36% of total calories). In addition to the alcohol group (A), both pair-fed (PF) and ad libitum-fed control (C) groups were included in each diet regimen. Basal levels of corticosterone and the adrenocortical response to stress were measured in dams on days 11, 16, or 21 of gestation. Plasma levels of corticosterone-binding globulin (CBG) were also measured on gestation days 16 and 21. Maternal adrenal weights, basal corticosterone levels, the adrenocortical response to stress, and the corticoid stress increment were all significantly increased in A compared to both PF and C females. Plasma CBG levels of A females were similar to or less than those of PF and C females. Thus alcohol consumption significantly increased maternal pituitary-adrenal activity as early as day 11 of gestation and these effects on hormonal function increased as gestation progressed. This adrenocortical hyperactivity was relatively unaffected by maternal nutritional status and thus appears specific to alcohol.

Pineal function during ethanol intoxication, dependence, and withdrawal

Pineal melatonin and serotonin content were determined during one to four days of continuous intoxication, and during the alcohol withdrawal syndrome. The nocturnal rise in pineal melatonin was blunted in continuously intoxicated animals, however this was found to be unrelated to duration of treatment. The initial dependent-intoxicated phase of the alcohol withdrawal syndrome produced a reduction of nocturnal pineal melatonin content with a concomitant elevation in pineal serotonin. The overt withdrawal phase of the alcohol withdrawal syndrome had no effect on pineal melatonin or serotonin content. This data suggests that ethanol may perturb pineal melatonin synthesis either directly, or indirectly by altered receptor function. Contrary to our expectations the pineal may not be a useful model to probe the physiology of increased noradrenergic neurotransmission produced by ethanol withdrawal.

Clinical neuroendocrinology and neuropharmacology of alcohol withdrawal

A number of alcohol research groups have measured anterior and posterior pituitary hormones, the endogenous opiates, CNS peptides, and putative neurotransmitters during alcohol withdrawal. The data are often complex and contradictory, though a number of themes have emerged. Activity of the hypothalamic-pituitary-adrenal axis (HPA) is increased during chronic alcohol exposure and appears to remain altered for at least 2 to 4 weeks after cessation of drinking. There is increased turnover of norepinephrine and enhanced binding of CNS adrenergic receptors. By contrast, there are decreases in CNS activity of select endogenous opiates and GABA. Other CNS compounds that may play a role in alcohol withdrawal are prolactin, thyrotropin-releasing hormone (TRH), vasopressin, cyclic 3'5'-adenosine monophophate (cAMP), Delta-sleep-inducing peptide (DSIP), and iron. Despite many studies in humans and animals, the roles of CNS dopamine and serotonin in withdrawal remain unclear. A number of peptides, including cholecystokinin (CCK), neurotensin, and bombesin, have been shown to interact with the CNS actions of alcohol and may play a role in alcohol withdrawal. Inadequate work has been performed on acetylcholine (ACh), human growth hormone (HGH) and luteinizing hormone (LH). Studies of the recently identified GABA-benzodiazepine-barbituate receptor complex indicate that this system is likely to be involved in the pathophysiology of alcohol withdrawal. Perturbation studies with corticotropin-releasing factor (CRF) and TRH (with measures of ACTH and cortisol and TSH and prolactin, respectively), may identify patients with withdrawal-related autonomic dysfunction.

Effects of drug and alcohol abuse upon pituitary-testicular function in adolescent males

To assess the effects of drug and alcohol abuse (DAA) on the physical changes and hormones of puberty in adolescents, 26 males (13 5/12-22 years) enrolled in a drug rehabilitation program were examined. In 22 subjects four timed blood samples were obtained sequentially at 15 minute intervals for measurement of serum concentrations of testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and dehydroepiandrosterone sulfate (DHAS). The mean duration of DAA was 3.7 years, with marijuana and alcohol being the most frequently abused substances. The study subjects were compared to a matched control group of non-substance-abusing teenagers. All heights and weights of the DAA subjects fell within two standard deviations of the mean on the Tanner Growth Charts and no statically significant differences in the Tanner stages of sexual maturation were found between the DAA and control groups. The mean (+/- SD) testosterone level of the DAA group (221 +/- 109 ng/dl) was less than half that of the control group (477 +/- 193 ng/dl, p less than 0.001). Mean LH concentration in the DAA group (3.9 +/- 3.0 mIU/ml) was significantly less than that of the control group (10 +/- 4.9 mIU/ml, p less than 0.01). In both the DAA and control populations there was a significant (p less than 0.01) correlation between serum concentrations of LH and testosterone. The mean FSH level of the DAA group (3.3 +/- 1.1 mIU/ml) was significantly less (p less than 0.02) than that of the control group (4.7 +/- 1.9 mIU/ml). To assess the effects of treatment, six boys underwent repeat blood sampling 7-12 months after drug and alcohol withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocortical hormones and brain growth: reversibility and differential sensitivity during development

The brain growth that follows adrenalectomy can be arrested by corticosterone replacement. Administered daily in combination with deoxycorticosterone, the brain and body conditions of intact rats are closely matched. Using this combination dose (corticosterone, 7.0 mg/kg; deoxycorticosterone, 1.0 mg/kg), hormonal replacement was systematically administered and withheld in a balanced design in order to assess the relative sensitivity of brain tissue to corticosteroids across time, and to determine if brain growth suppressed during one phase could recover upon hormone withdrawal during a second phase. Female forebrains were less sensitive to the hormones during an early phase which spanned ages 27 to 46 days. In contrast, 70 to 80% of potential growth was suppressed by replacement during a later period (ages 46 to 65 days). Brain size differences included weight and forebrain length, width, and depth. Hind brains were more sensitive to hormone replacement during phase 1. However, this suppressed growth was completely regained after hormone withdrawal during phase 2. On the other hand, growth that had occurred in the absence of adrenal steroids was not reversed, only arrested, by subsequent administration. We conclude that the rat brain became increasingly sensitive to the suppressive influence of adrenal steroids as females matured from juveniles to adults. Coupled with this sensitivity was the ability--apparently complete--to recover from steroid-induced brain growth suppression.

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

In vitro studies have shown that acetaldehyde is a more potent inhibitor of testicular steroidogenesis than ethanol. The present study examined the in vivo role of acetaldehyde in ethanol-induced reduction of testosterone by (1) determining the levels of acetaldehyde to which the testes were exposed subsequent to acute ethanol administration to mice; and (2) examining the effect of ethanol on testosterone in animals subsequent to drug pretreatment which decreased or increased ethanol-derived acetaldehyde. Ethanol-induced (3 g/kg) depression of testosterone was dependent upon gonadotropin stimulation. The increase in hCG-induced testosterone was suppressed (P less than 0.01) in ethanol- as compared to saline-treated animals [39.8 +/- 2.6 (S.E.M.) vs 28.1 +/- 2.3 ng/ml]. Pargyline (100 mg/kg) or cyanamide (8.4 mg/kg) increased (P less than 0.05) plasma and testicular acetaldehyde, while having no effect on the testosterone response to ethanol. Similarly, 4-methylpyrazole (25 mg/kg) reduced blood and testicular acetaldehyde to nondetectable levels, while having no effect on testosterone. Testicular acetaldehyde was lower (P less than 0.001) than plasma levels (14 +/- 2 vs 2.0 +/- 0.2 microM). This functional blood-testis barrier to acetaldehyde could be explained by testicular aldehyde dehydrogenases in the mitochondria (Km for acetaldehyde = 1.5 microM) and in the cytosol (Km = 123 microM) whose maximal activities totaled to more than 25-fold greater than that of testicular alcohol dehydrogenase (ADH). ADH was concentrated in the Leydig cells, while aldehyde dehydrogenase was evenly distributed in the testis. Ethanol prevented further hCG-induced rises in testosterone rather than inhibiting testosterone production to below pre-ethanol values. The above data argue against a significant role of acetaldehyde in the in vivo response of testosterone to ethanol. Ethanol appears to impair gonadotropin-testicular receptor interaction in vivo.

Growth, enzymes and hormonal changes in offspring of alcohol-fed rats

Consumption of ethanol by rats during pregnancy reduces the body and brain weight of their fetuses and pups. The reduction is greater if the offspring are kept with their alcohol-fed mothers rather than with control surrogate mothers during lactation. The activity of several enzymes of the neuronal cell membranes (Na+, K+-ATPase, Ca2+-ATPase, acetylcholinesterase, 5'-nucleotidase) is also reduced. This decrease in enzyme activity may be related to the decrease in neuronal development and could produce profound alterations in brain function. Altered hypothalamic-hypophysial function may be partly responsible for developmental anomalies found in the fetal alcohol syndrome. The levels of plasma luteinizing hormone are lower in pups exposed prenatally to ethanol, and prolactin levels are much higher. Concentrations of ethanol were essentially the same in maternal blood and in the fetus. Acetaldehyde levels in the placenta, amniotic fluid and the remaining fetal tissue at days 15 and 19 of gestation were about 40-50% of those in maternal blood. Acetaldehyde may be important in the pathogenesis of the fetal alcohol syndrome.

Ethanol dependence and the pituitary adrenal axis in mice. II. Temporal analysis of dependence and withdrawal

The effects of ethanol dependence and withdrawal on pituitary hormone content and corticosterone release were investigated in AKR/J male mice in a vapor chamber. Both chronic ethanol inhalation and ethanol withdrawal were associated with increased adenohypophyseal-adrenocortical activity. Operationally, ethanol exposure was a stressor. Both physical dependence and withdrawal led to increased secretion/synthesis ratios of peptide hormones. The temporal pattern of pituitary ACTH-IR content changes was different from that of beta-endorphin-IR and alpha-MSH-IR. Differences in the pattern of ACTH-IR and alpha-MSH-IR most probably represent lobe-specific differences in the response to chronic ethanol exposure and withdrawal.

Ethanol dependence and the pituitary-adrenal axis in mice. I. Genotypic differences in hormone levels

Resting pituitary levels of beta-endorphin-(beta-EP-IR), ACTH-(ACTH-IR), and alpha-MSH-(alpha-MSH-IR)-like immunoreactive material were found to differ among 16 inbred mouse strains. Hormone levels correlated genetically with severity of withdrawal from ethanol, which also differed among the strains. Ethanol dependence led to reduced pituitary beta-EP-IR in 4 of 5 strains studied. After 24 hr of withdrawal, 3 of those 4 showed elevated pituitary beta-EP-IR. These results are consistent with the hypothesis that genetically-determined difference in pituitary hormone functioning underlie some of the genetically-determined differences in ethanol withdrawal severity.

Clinical pathology of alcohol

There is good though not conclusive evidence that a small to modest average daily intake of alcohol--that is, 20-30 g/day is associated with increased longevity due mainly to a reduction in death from cardiovascular disease. Larger average daily alcohol intakes--especially those in excess of 60 g/day for men and 40 g/day for women--are associated with gradually increasing morbidity and mortality rates from a variety of diseases. Alcohol may be unrecognised as the cause of somatic disease, which can occur without overt psychosocial evidence of alcohol abuse, unless the index of suspicion is high and a thorough drink history obtained. Laboratory tests for the detection and/or confirmation of alcohol abuse are useful but subject to serious limitations being neither as sensitive nor specific as sometimes believed. The value of random blood and/or breath alcohol measurements, in outpatients, as an aid to diagnosis of alcohol-induced organic disease is probably not sufficiently appreciated and, though relatively insensitive, is highly specific.

Inhibition of testosterone production by rat Leydig cells with ethanol and acetaldehyde: prevention of ethanol toxicity with 4-methylpyrazole

The toxic effects of ethanol and acetaldehyde on testosterone biosynthesis were examined in vitro using isolated Leydig cells prepared from adult rat testes. The ability of 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, to prevent the toxic effects of ethanol on testosterone production was investigated. Ethanol was found to inhibit gonadotropin-stimulated testosterone production in a dose dependent fashion. Concentrations of ethanol (25 mg/100 reduce testosterone levels by 44% as compared to the controls. Acetaldehyde at micromolar concentrations also inhibited testosterone biosynthesis. The addition of 4-methylpyrazole to the culture medium prevented the toxic effects of ethanol as determined by testosterone production. These studies suggest that ethanol per se may not directly inhibit testosterone biosynthesis. Rather, it would appear that acetaldehyde, the first product of ethanol metabolism, may be responsible for the toxic effects of ethanol upon Leydig cells at least in vitro.