Prolactin serum levels and alcohol craving - an analysis using Lesch's typology

Factors associated with the level of prolactin in patients under remission from Alcohol Use Disorder: A gender perspective

BACKGROUND

Prolactin mirrors the dopaminergic activity in the brain which is key to understanding alcohol use disorders (AUD). Still, patients with AUD are a heterogenous group and there seem to be gender differences in the relationship between alcohol use and the level of prolactin. In this study, we examined gender-wise relationship of alcohol use trait- and state-related factors with the level of prolactin among AUD inpatients in remission.

METHODS

This cross-sectional study examined the level of prolactin along with general patient characteristics and alcohol use trait- and state-related factors that could influence the level of prolactin in 112 AUD inpatients at three rehabilitation clinics in Norway. Logistic regression was performed to identify the gender-specific predictors of level of prolactin.

RESULTS

Male and female AUD patients had similar level of prolactin. Among females, younger age, early alcohol debut, and absence of parental drinking problem predicted higher level of prolactin. In males, presence of other substance dependence predicted a lower level of prolactin.

CONCLUSIONS

There were gender differences in the factors associated with the level of prolactin among the AUD patients. Especially in the female AUD patients under remission, alcohol use trait-related factors were better predictors of the level of prolactin than the alcohol use state-related factors, indicating that individuals might characteristically have varying degree of dopamine reactivity.

Antisocial Personality Disorder Among Patients in Treatment for Alcohol Use Disorder (AUD): Characteristics and Predictors of Early Relapse or Drop-Out

Background

Patients with alcohol use disorders (AUD) vary significantly in many clinically important characteristics making them a heterogenous group. AUD patients with comorbid antisocial personality disorder (ASPD) form an important sub-group, and studies indicate that these patients may have poorer treatment outcomes. Therefore, we aimed to investigate the characteristics of AUD inpatients with comorbid ASPD and identify predictors of early relapse or treatment drop-out in these patients.

Methods

In a longitudinal study of AUD patients (n = 113; 30 females; aged 27 to 72 years) in treatment at three residential rehabilitation clinics in Norway, we used interviews and self-report questionnaires to collect data on alcohol use, mental health, and trauma experience. In addition, we assessed biochemical parameters. The patients were followed up at 6 weeks to identify early relapse or drop-out.

Results

Prevalence of ASPD among AUD patients was 15%. AUD patients with comorbid ASPD were exclusively male, of younger age, and reported more childhood trauma, and adult attention-deficit-hyperactivity-disorder symptoms. They reported more hazardous drinking behavior and more often had dependence on substances in addition to alcohol. The presence of ASPD did not predict early relapse or drop-out. However, early relapse or drop-out in ASPD patients was associated with childhood and adult trauma, younger age of drinking debut, and higher baseline prolactin levels.

Conclusion

AUD patients with ASPD had different clinical characteristics to other AUD patients and they had specific predictors of early relapse or drop-out. Our findings indicate that the early relapse or drop-out among AUD patients with ASPD may be attributed to environmental and possibly biological vulnerability. However, further studies with larger sample size are warranted to confirm these preliminary associations.

Pharmacologically induced alcohol craving in treatment seeking alcoholics correlates with alcoholism severity, but is insensitive to acamprosate

Modulation of alcohol craving induced by challenge stimuli may predict the efficacy of new pharmacotherapies for alcoholism. We evaluated two pharmacological challenges, the α(2)-adrenergic antagonist yohimbine, which reinstates alcohol seeking in rats, and the serotonergic compound meta-chlorophenylpiperazine (mCPP), previously reported to increase alcohol craving in alcoholics. To assess the predictive validity of this approach, the approved alcoholism medication acamprosate was evaluated for its ability to modulate challenge-induced cravings. A total of 35 treatment seeking alcohol dependent inpatients in early abstinence were randomized to placebo or acamprosate (2997 mg daily). Following two weeks of medication, subjects underwent three challenge sessions with yohimbine, mCPP or saline infusion under double blind conditions, carried out in counterbalanced order, and separated by at least 5 days. Ratings of cravings and anxiety, as well as biochemical measures were obtained. In all, 25 subjects completed all three sessions and were included in the analysis. Cravings were modestly, but significantly higher following both yohimbine and mCPP challenge compared with saline infusion. The mCPP, but not yohimbine significantly increased anxiety ratings. Both challenges produced robust ACTH, cortisol and prolactin responses. There was a significant correlation between craving and the degree of alcoholism severity. Acamprosate administration did not influence craving. Both yohimbine and mCPP challenges lead to elevated alcohol craving in a clinical population of alcoholics, and these cravings correlate with alcoholism severity. Under the experimental conditions used, alcohol cravings induced by these two stimuli are not sensitive to acamprosate at clinically used doses.

Increased intake of ethanol and dietary fat in galanin overexpressing mice

Evidence suggests that the orexigenic peptide, galanin (GAL), in the hypothalamic paraventricular nucleus (PVN) has a role in stimulating the consumption of ethanol, in addition to a high-fat diet. This possibility was further examined in mutant mice that overexpress the GAL gene. Two sets of GAL-overexpressors (GALOE) compared with wild-type (WT) controls, maintained on laboratory chow and water, were trained to voluntarily drink increasing concentrations of ethanol, from 3 to 15%. In the GALOE versus WT mice, the results revealed the following: (1) a 35-40% increase in ethanol intake and ethanol preference, which was evident only at the highest (15%) ethanol concentration, in male but not female mice, and was seen with comparisons to littermate and nonlittermate WT controls, (2) a significantly larger, 60-75% increase in ethanol intake and ethanol preference after a day of food deprivation, again only in male GALOE mice, (3) no change in consumption of sucrose or quinine solutions in preference tests, and (4) a 55% increase in consumption of a fat-rich diet during a 2-h test period, in both male and female GALOE mice. These results obtained with overexpression of the GAL gene provide strong support for a physiological role of this peptide in stimulating the consumption of ethanol and a fat-rich diet. They reveal gender differences in the behavioral phenotype, which may reflect GAL's functional relationship to reproductive hormones in the stimulation of consummatory behavior.

Herp mRNA expression in patients classified according to Lesch's typology

Chronic alcoholism is associated with hyperhomocysteinemia. Herp (homocysteine-induced endoplasmic reticulum [ER] protein) levels are elevated as a response to ER stress prior to mitochondrial dysfunction and cell death. The Lesch classification system has been applied in many studies and has been found useful. This study was undertaken to assess Herp mRNA expression in actively drinking patients with alcoholism who were classified according to Lesch's typology. Herp mRNA expression levels were measured by quantitative PCR in the blood of 76 male alcoholic patients. Patients were classified according to Lesch's typology (type I-IV). With respect to Lesch's typology, a significant difference in Herp mRNA expression regarding the four subtypes could be shown (F[3,72]=2.83, P=.044). In a logistic regression model (dependent variable Herp dichotomized by a median-split; adjusted for age and homocysteine levels) the subtype II differed statistically significant from the others (odds ratio, 5.75; 95% confidence interval, 2.07-15.98; P=.001). Type II alcoholic patients had a statistically significant higher expression of Herp mRNA due to upregulation of the expression of this neuroprotective cell non-chaperone by toxic effects of ethanol. These findings might explain why type II patients do not express severe withdrawal symptomatology (i.e., withdrawal seizures). These findings may be useful in the understanding and treatment considerations of different subtypes of alcohol dependence.

Alcoholism, craving, and hormones: the role of leptin, ghrelin, prolactin, and the pro-opiomelanocortin system in modulating ethanol intake

Evidence is growing that appetite regulating peptides such as leptin and ghrelin, but also other hormones including prolactin are altered in alcoholism. The brain pro-opiomelanocortin (POMC) system which has important mediating roles in alcohol intake also has important functions in prolactin regulation and energy homeostasis. Furthermore, it has been demonstrated to be functionally integrated with leptin regulation. The satiety factor leptin seems to be counteracted by the gut-derived peptide ghrelin which increases hunger and food intake. Consequently, the POMC system may have a role in integrating regulation of alcohol effects and these seemingly disparate regulatory systems. The goal of this mini-review is to discuss the results of some recent investigations of the potential interactions of these systems with acute and chronic alcohol responses.

Genetics of Lesch's typology of alcoholism

It is widely accepted that dopamine and serotonin (5-HT) neurotransmission can be critically involved in the development of alcohol abuse and alcohol dependence. Lesch's typology of alcoholism has been gaining increasing popularity as it qualitatively differentiates patients into different treatment response subgroups. The aim of the present study was to evaluate a possible genetic background of Lesch's typology with special emphasis placed on dopamine- and serotonin-related genes. 122 alcoholics (the mean age: 35+/-9 years) were investigated. According to Lesch's typology, 58 patients were of type I, 36 patients of type II, 11 patients of type III, and 17 patients of type IV. Alcohol drinking and family history was assessed by means of a structured interview, based on the Semi-Structured Assessment for the Genetics of Alcoholism. 150 control subjects without psychiatric disorders were also recruited. The control group was ethnically-, age- and gender-matched to the patients. The DRD2 TaqIA, exon 8, and promoter -141C ins/del polymorphisms as well as COMT Val158Met, 5HTT 44 bp del in promoter, and DAT 40 bp VNTR polymorphisms were detected by means of PCR. No significant differences were observed when the whole group of alcoholics and the controls were compared. Similarly, there were no differences between either the Lesch type I or type II alcoholics and the control subjects. No significant differences were observed between type I and type II alcoholics. Alleles frequencies were not calculated for the Lesch type III and type IV alcoholics since the number of patients was too small. The present results argue against any major role of the investigated polymorphisms in either Lesch type I or type II alcoholism. More comprehensive studies are needed to define the role of the investigated polymorphisms in Lesch type III and type IV alcoholism.

Role of Appetite-Regulating Peptides in Alcohol Craving: An Analysis in Respect to Subtypes and Different Consumption Patterns in Alcoholism

BACKGROUND

A role of appetite-regulating peptides like leptin and ghrelin in the neurobiology of alcohol craving has been proposed by several studies. Aim of this analysis was to search for differences regarding an association between these peptides and alcohol craving with respect to different subtypes and beverage consumption patterns in patients with alcohol dependence.

METHODS

We analyzed a sample of 188 patients at admission for alcohol detoxification regarding leptin and ghrelin (n=117) serum levels. Craving was measured using the Obsessive Compulsive Drinking Scale (OCDS). Patients were classified according to Lesch's typology of alcohol dependence and according to their preferred type of alcoholic beverage (beer, wine, spirits).

RESULTS

Using general linear models to analyze a possible interaction between subtypes and leptin/ghrelin levels with respect to craving, we found a significant positive association for leptin in patients of Lesch's types 1 and 2, and in patients consuming beer or wine. Ghrelin levels showed a significant trend regarding an association with craving in patients of Lesch's type 1. In the other subgroups we found no significant results.

CONCLUSIONS

Our findings show that appetite-regulating peptides may be of special importance regarding alcohol craving in subtypes of patients. This may explicate at least in part previous contradictory findings.