The paraventricular thalamus provides a polysynaptic brake on limbic CRF neurons to sex-dependently blunt binge alcohol drinking and avoidance behavior in mice.

Bed nucleus of the stria terminalis (BNST) neurons that synthesize corticotropin-releasing factor (CRF) drive binge alcohol drinking and anxiety. Here, we found that female C57BL/6J mice binge drink more than males and have greater basal BNSTCRF neuron excitability and synaptic excitation. We identified a dense VGLUT2 + synaptic input from the paraventricular thalamus (PVT) that releases glutamate directly onto BNSTCRF neurons but also engages a large BNST interneuron population to ultimately inhibit BNSTCRF neurons, and this polysynaptic PVTVGLUT2-BNSTCRF circuit is more robust in females than males. Chemogenetic inhibition of the PVTBNST projection promoted binge alcohol drinking only in female mice, while activation reduced avoidance behavior in both sexes. Lastly, repeated binge drinking produced a female-like phenotype in the male PVT-BNSTCRF excitatory synapse without altering the function of PVTBNST neurons per se. Our data describe a complex, feedforward inhibitory PVTVGLUT2-BNSTCRF circuit that is sex-dependent in its function, behavioral roles, and alcohol-induced plasticity.

Vertical Sleeve Gastrectomy Attenuates Hedonic Feeding Without Impacting Alcohol Drinking in Rats.

OBJECTIVE: Roux-en-Y gastric bypass surgery and vertical sleeve gastrectomy (VSG) are the most commonly performed bariatric procedures. Whereas studies report new-onset alcohol misuse following Roux-en-Y gastric bypass, the impact of VSG on alcohol intake is less clear. Hedonic feeding, alcohol drinking, and hypothalamic obesity-related gene expression following VSG were evaluated. METHODS: Male Long-Evans rats underwent VSG or sham surgery. To evaluate hedonic feeding, rats received a high-fat diet following behavioral satiation on chow. Alcohol (5%-10% v/v) drinking was assessed in a two-bottle choice paradigm. Finally, polymerase chain reaction array evaluated gene expression. RESULTS: VSG induced moderate but significant weight loss. Sham rats significantly escalated high-fat diet intake following behavioral satiation, an effect significantly reduced in VSG rats. A moderate decrease in alcohol intake was observed in VSG rats at low (5%) alcohol concentration. However, overall, no significant between-group differences were evident. Key hypothalamic orexigenic transcripts linked to stimulation of food and alcohol intake were significantly decreased in VSG rats. CONCLUSIONS: VSG attenuated hedonic feeding without impacting alcohol drinking, an effect potentially mediated by alterations in genetic information flow within the hypothalamus. Importantly, these data highlight VSG as an effective bariatric procedure with a potentially reduced risk of developing alcohol use disorder.

Problem Drinking, Alcohol Expectancy, and Thalamic Resting-State Functional Connectivity in Nondependent Adult Drinkers.

Alcohol misuse is associated with thalamic dysfunction. The thalamus comprises subnuclei that relay and integrate information between cortical and subcortical structures. However, it is unclear how the subnuclei contribute to thalamic dysfunctions in problem drinking. We investigated resting-state functional connectivity (rsFC) of thalamic subregions in 107 nondependent drinkers (57 women), using masks delineated by white matter tractography. Thalamus was parceled into motor, somatosensory, visual, premotor, frontal association, parietal association, and temporal association subregions. Whole-brain linear regression, each against Alcohol Use Disorders Identification Test (AUDIT) and positive alcohol expectancy (AE) score with age as a covariate, was performed for each seed, for men and women combined, and separately. Overall, problem drinking was associated with increased thalamic connectivities, whereas AE was associated with a mixed pattern of increased and decreased connectivities. Motor, premotor, somatosensory, and frontal association thalamic connectivity with bilateral caudate head was positively correlated with AUDIT score in men and women combined. Connectivity of the right caudate head with frontal association and premotor thalamus was also positively correlated with AE score in men and women combined. In contrast, motor and premotor thalamic connectivity with a number of cortical and subcortical structures showed sex differences in the correlation each with AUDIT and AE score. In mediation analyses, AE score completely mediated the correlation between thalamic caudate connectivity and AUDIT score, whereas the model where AE contributed to problem drinking and, in turn, altered thalamic caudate connectivity was not supported. To conclude, thalamic subregional rsFCs showed both shared and distinct changes and sex differences in association with problem drinking and AE. Increased thalamic caudate connectivity may contribute to problem drinking via enhanced AE. The findings suggest the importance of examining thalamic subdivisions and sex in investigating the functional roles of thalamus in problem drinking.

Effects of embryonic ethanol exposure at low doses on neuronal development, voluntary ethanol consumption and related behaviors in larval and adult zebrafish: Role of hypothalamic orexigenic peptides.

Embryonic exposure to ethanol is known to affect neurochemical systems in rodents and increase alcohol drinking and related behaviors in humans and rodents. With zebrafish emerging as a powerful tool for uncovering neural mechanisms of numerous diseases and exhibiting similarities to rodents, the present report building on our rat studies examined in zebrafish the effects of embryonic ethanol exposure on hypothalamic neurogenesis, expression of orexigenic neuropeptides, and voluntary ethanol consumption and locomotor behaviors in larval and adult zebrafish, and also effects of central neuropeptide injections on these behaviors affected by ethanol. At 24h post-fertilization, zebrafish embryos were exposed for 2h to ethanol, at low concentrations of 0.25% and 0.5%, in the tank water. Embryonic ethanol compared to control dose-dependently increased hypothalamic neurogenesis and the proliferation and expression of the orexigenic peptides, galanin (GAL) and orexin (OX), in the anterior hypothalamus. These changes in hypothalamic peptide neurons were accompanied by an increase in voluntary consumption of 10% ethanol-gelatin and in novelty-induced locomotor and exploratory behavior in adult zebrafish and locomotor activity in larvae. After intracerebroventricular injection, these peptides compared to vehicle had specific effects on these behaviors altered by ethanol, with GAL stimulating consumption of 10% ethanol-gelatin more than plain gelatin food and OX stimulating novelty-induced locomotor behavior while increasing intake of food and ethanol equally. These results, similar to those obtained in rats, suggest that the ethanol-induced increase in genesis and expression of these hypothalamic peptide neurons contribute to the behavioral changes induced by embryonic exposure to ethanol.

Model of voluntary ethanol intake in zebrafish: effect on behavior and hypothalamic orexigenic peptides.

Recent studies in zebrafish have shown that exposure to ethanol in tank water affects various behaviors, including locomotion, anxiety and aggression, and produces changes in brain neurotransmitters, such as serotonin and dopamine. Building on these investigations, the present study had two goals: first, to develop a method for inducing voluntary ethanol intake in individual zebrafish, which can be used as a model in future studies to examine how this behavior is affected by various manipulations, and second, to characterize the effects of this ethanol intake on different behaviors and the expression of hypothalamic orexigenic peptides, galanin (GAL) and orexin (OX), which are known in rodents to stimulate consumption of ethanol and alter behaviors associated with alcohol abuse. Thus, we first developed a new model of voluntary intake of ethanol in fish by presenting this ethanol mixed with gelatin, which they readily consume. Using this model, we found that individual zebrafish can be trained in a short period to consume stable levels of 10% or 20% ethanol (v/v) mixed with gelatin and that their intake of this ethanol-gelatin mixture leads to pharmacologically relevant blood ethanol concentrations which are strongly, positively correlated with the amount ingested. Intake of this ethanol-gelatin mixture increased locomotion, reduced anxiety, and stimulated aggressive behavior, while increasing expression of GAL and OX in specific hypothalamic areas. These findings, confirming results in rats, provide a method in zebrafish for investigating with forward genetics and pharmacological techniques the role of different brain mechanisms in controlling ethanol intake.

Structural brain differences in alcohol-dependent individuals with and without comorbid substance dependence.

BACKGROUND: Over 50% of individuals with alcohol use disorders (AUD) also use other substances; brain structural abnormalities observed in alcohol dependent individuals may not be entirely related to alcohol consumption. This MRI study assessed differences in brain regional tissue volumes between short-term abstinent alcohol dependent individuals without (ALC) and with current substance use dependence (polysubstance users, PSU). METHODS: Nineteen, one-month-abstinent PSU and 40 ALC as well as 27 light-drinkers (LD) were studied on a 1.5 T MR system. Whole brain T1-weighted images were segmented automatically into regional gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) volumes. MANOVA assessed group differences of intracranial volume-normalized tissue volumes of the frontal, parietal, occipital, and temporal lobes and regional subcortical GM volumes. The volumetric measures were correlated with neurocognitive measures to assess their functional relevance. RESULTS: Despite similar lifetime drinking and smoking histories, PSU had significantly larger normalized WM volumes than ALC in all lobes. PSU also had larger frontal and parietal WM volumes than LD, but smaller temporal GM volumes and smaller lenticular and thalamic nuclei than LD. ALC had smaller frontal, parietal, and temporal GM, thalamic GM and cerebellar volumes than LD. ALC had more sulcal CSF volumes than both PSU and LD. CONCLUSION: One-month-abstinent ALC and PSU exhibited different patterns of gross brain structural abnormalities. The larger lobar WM volumes in PSU in the absence of widespread GM volume loss contrast with widespread GM atrophy in ALC. These structural differences may demand different treatment approaches to mitigate specific functionally relevant brain abnormalities.

The effects of inhibitory control training on alcohol consumption, implicit alcohol-related cognitions and brain electrical activity.

This study aimed to replicate findings that alcohol consumption and positive implicit beer-related cognitions can be reduced using inhibitory control (IC) training, with the addition of an active training control. Frontal EEG asymmetry, an objective psychophysiological index of approach motivation, was used as a dependent measure to examine training outcomes. Participants were randomly assigned to one of two IC training conditions (Beer NoGo or Beer Go) or a Brief Alcohol Intervention (BAI) (i.e. the active training control). The IC training tasks consistently paired a stimulus that required a response with images of water (Beer NoGo) or images of beer (Beer Go). Alcohol consumption and implicit beer-related cognitions were measured at pre-training, post-training and at one week follow-up. Frontal EEG asymmetry was recorded during a passive image viewing task that presented neutral, healthy, and beer stimuli - at pre-training, post-training and follow-up. Participants in the Beer NoGo and BAI conditions consumed less beer in a taste test immediately after training than Beer Go participants, suggesting that IC training may be as effective as the already established BAI. The taste test findings were in line with the frontal EEG asymmetry data, which indicated that approach motivation for beer stimuli was altered in the expected directions. However, the positive correlation between post-training frontal EEG asymmetry data and taste test consumption was not significant. While there were no significant changes in implicit beer-related cognitions following training, a trending positive relationship between implicit beer-related cognitions at post-training and taste test consumption was reported. Further exploration addressing the limitations of the current study is required in order to clarify the implications of these findings.

Diffusion tensor imaging of white matter networks in individuals with current and remitted alcohol use disorders and comorbid conditions.

Individuals with alcohol use disorders show white matter abnormality relative to normal samples, but differences in white matter profiles have not yet been investigated as a function of abstinence. Individuals with current alcohol use disorders (AUD-C; n = 10), individuals with alcohol use disorders in remission for at least 1 year (AUD-R; n = 9), and healthy control participants (HC; n = 15) matched to alcohol groups on age and smoking status underwent MRI. Diffusion tensor imaging (DTI) data were analyzed using tract-based spatial statistics (TBSS). Compared with HC, AUD-C showed reduced axial diffusivity in bilateral frontal and temporal white matter. In AUD-R, lower fractional anisotropy relative to HC was widespread in bilateral parietal regions. A combined AUD-C and AUD-R group had decreased fractional anisotropy primarily in the fornix and thalamus. In conclusion, AUD-R manifested damage in parietal regions integral to processing of visuospatial information and self-awareness whereas AUD-C showed abnormal diffusivity in fronto-temporal regions that regulate impulsivity, attention, and memory. As a combined group, AUD individuals exhibited abnormality in subcortical areas associated with sensory processing and memory. White matter differences in individuals with AUD may be attributable to premorbid vulnerability or persisting effects of alcohol abuse, but the pattern of abnormality across groups suggests that these abnormalities may be secondary to alcohol use.

Acute administration of vinpocetine, a phosphodiesterase type 1 inhibitor, ameliorates hyperactivity in a mice model of fetal alcohol spectrum disorder.

BACKGROUND: Maternal alcohol use during pregnancy causes a continuum of long-lasting disabilities in the offspring, commonly referred to as fetal alcohol spectrum disorder (FASD). Attention-deficit/hyperactivity disorder (ADHD) is possibly the most common behavioral problem in children with FASD and devising strategies that ameliorate this condition has great clinical relevance. Studies in rodent models of ADHD and FASD suggest that impairments in the cAMP signaling cascade contribute to the hyperactivity phenotype. In this work, we investigated whether the cAMP levels are affected in a long-lasting manner by ethanol exposure during the third trimester equivalent period of human gestation and whether the acute administration of the PDE1 inhibitor vinpocetine ameliorates the ethanol-induced hyperactivity. METHODS: From postnatal day (P) 2 to P8, Swiss mice either received ethanol (5g/kg i.p.) or saline every other day. At P30, the animals either received vinpocetine (20mg/kg or 10mg/kg i.p.) or vehicle 4h before being tested in the open field. After the test, frontal cerebral cortices and hippocampi were dissected and collected for assessment of cAMP levels. RESULTS: Early alcohol exposure significantly increased locomotor activity in the open field and reduced cAMP levels in the hippocampus. The acute treatment of ethanol-exposed animals with 20mg/kg of vinpocetine restored both their locomotor activity and cAMP levels to control levels. CONCLUSIONS: These data lend support to the idea that cAMP signaling system contribute to the hyperactivity induced by developmental alcohol exposure and provide evidence for the potential therapeutic use of vinpocetine in FASD.

Ethanol impairs activation of retinoic acid receptors in cerebellar granule cells in a rodent model of fetal alcohol spectrum disorders.

BACKGROUND: Ethanol is the main addictive and neurotoxic constituent of alcohol. Ethanol exposure during embryonic development causes dysfunction of the central nervous system (CNS) and leads to fetal alcohol spectrum disorders. The cerebellum is one of the CNS regions that are particularly vulnerable to ethanol toxic effects. Retinoic acid (RA) is a physiologically active metabolite of vitamin A that is locally synthesized in the cerebellum. Studies have shown that RA is required for neuronal development, but it remains unknown if ethanol impairs RA signaling and thus induces neuronal malformations. In this study, we tested the hypothesis that ethanol impairs the expression and activation of RA receptors in cerebellum and in cerebellar granule cells. METHODS: The cerebellum of ethanol unexposed and exposed pups was used to study the expression of retinoic acid receptors (RARs or RXRs) by immunohistochemistry and by Western blot analysis. We also studied the effect of ethanol on expression of RA receptors in the cerebellar granule cells. Activation of RA receptors (DNA-binding activities) in response to high-dose ethanol was determined by electrophoretic mobility shift and supershift assays. RESULTS: Findings from these studies demonstrated that ethanol exposure reduced the expression of RARalpha/gamma while it increased the expression of RXRalpha/gamma in the cerebellum and in cerebellar granule neurons. Immuno-histological studies further strengthened the expression pattern of RA receptors in response to ethanol. The DNA-binding activity of RARs was reduced, while DNA-binding activity of RXRs was increased in response to ethanol exposure. CONCLUSION: For the first time, our studies have demonstrated that high-dose ethanol affects the expression and activation of RA receptors, which could impair the signaling events and induce harmful effects on the survival and differentiation of cerebellar granule cells. Taken together, these findings could provide insight into the treatment options for brain defects caused by excessive ethanol exposure, such as in Fetal Alcohol Spectrum Disorders.

Procysteine stimulates expression of key anabolic factors and reduces plantaris atrophy in alcohol-fed rats.

BACKGROUND: Long-term alcohol ingestion may produce severe oxidant stress and lead to skeletal muscle dysfunction. Emerging evidence has suggested that members of the interleukin-6 (IL-6) family of cytokines play diverse roles in the regulation of skeletal muscle mass. Thus, our goals were (i) to minimize the degree of oxidant stress and attenuate atrophy by supplementing the diets of alcohol-fed rats with the glutathione precursor, procysteine, and (ii) to identify the roles of IL-6 family members in alcoholic myopathy. METHODS: Age- and gender-matched Sprague-Dawley rats were fed the Lieber-DeCarli liquid diet containing either alcohol or an isocaloric substitution (control diet) for 35 weeks. Subgroups of alcohol-fed rats received procysteine (0.35%, w/v) for the final 12 weeks. Plantaris morphology was assessed by hematoxylin and eosin staining. Major components of glutathione metabolism were determined using assay kits. Real-time PCR was used to determine expression levels of several genes. RESULTS: Plantaris muscles from alcohol-fed rats displayed extensive atrophy, as well as decreased glutathione levels, decreased activities of glutathione reductase and glutathione peroxidase, decreased superoxide dismutase (SOD)-2 (Mn-SOD2), and increased NADPH oxidase-1 gene expression-each indicative of significant oxidant stress. Alcohol also induced gene expression of catabolic factors including IL-6, oncostatin M, atrogin-1, muscle ring finger protein-1, and IGFBP-1. Procysteine treatment attenuated plantaris atrophy, restored glutathione levels, and increased catalase, Cu/Zn-SOD1, and Mn-SOD2 mRNA expression, but did not reduce other markers of oxidant stress or levels of these catabolic factors. Instead, procysteine stimulated gene expression of anabolic factors such as insulin-like growth factor-1, ciliary neurotrophic factor, and cardiotrophin-1. CONCLUSIONS: Procysteine significantly attenuated, but did not completely abrogate, alcohol-induced oxidant stress or catabolic factors. Rather, procysteine minimized the extent of plantaris atrophy by inducing components of several anabolic pathways. Therefore, anti-oxidant treatments such as procysteine supplementation may benefit individuals with alcoholic myopathy.

Altered brain activation by a false recognition task in young abstinent patients with alcohol dependence.

BACKGROUND: Heavy alcohol intake induces both structural and functional changes in the central nervous system. Recent research developments converged on the idea that even in patients with alcohol dependence without apparent structural brain changes, some cognitive impairment exists, and associated functional change could be visualized by neuroimaging techniques. However, these data were from old (more than 50 years) patients using working memory and response inhibition tasks. Whether young abstinent patients show aberrant signs of brain activation is a matter of interest, specifically by the long-term memory retrieval task. METHODS: Subjects were 9 young patients with alcohol dependence with long-term abstinent (8 males and 1 female) and age- and education-matched 9 healthy controls (7 males and 2 females). We used a modified false recognition task in a functional MRI study. RESULTS: The young patients with alcohol dependence showed reduced activation in the right dorsolateral prefrontal cortex, anterior cingulate cortex (ACC), left pulvinar in the thalamus, and in the right ventral striatum, although behavioral performances and regional patterns of brain activation were similar between patients and controls. CONCLUSIONS: Long-term memory retrieval induced altered activations in prefrontal lobes, ACC, thalamus, and ventral striatum in young patients with alcohol dependence. These findings were correspondent to deficits of goal directed behavior, monitoring the erroneous responses, memory function, and drug-seeking behavior. Furthermore, these reduced activations can be considered as latent "lesions," suggesting subclinical pathology in alcoholic brains.

Effects of chronic drinking on verb generation: an event related potential study.

In alcohol dependent individuals, abnormalities in brain functioning have been revealed using event-related potential (ERP) methods. In the present study, we investigated whether in non-alcohol dependent drinkers functioning of the brain is also compromised as a function of recent and lifetime drinking history (LDH). An ERP verb generation task consisting of two conditions (generating verbs describing the use of visually presented nouns versus reading nouns aloud) was used; subtracting ERPs in the latter condition from those in the former should reveal the sequence of brain processes involved in verb generation. Four groups were included, consisting of individuals drinking either lightly, moderately, heavily, or excessively (overall mean age 46.6 years). Participants were sober at the time of testing. Although the excessive group had the highest per cent retrieval errors, there was no continuous relationship between this score and amount of alcohol consumption. However, number of glasses per week affected differential ERPs associated with verb generation both at short (120-220 ms, mid-frontal sites) and at longer latencies (from 700 ms on),left-temporal and right-frontal electrode sites (T7, F6). It is concluded that moderate, heavy, and excessive drinkers, compared to light drinkers, show abnormal brain potentials associated with verb generation over frontal and temporal areas. Moderate to excessive drinking alters some but not all brain processes involved in verb generation. In particular the frontal and temporal brain areas appear to be vulnerable for the effects of chronic lifetime drinking.

Ethanol intake increases galanin mRNA in the hypothalamus and withdrawal decreases it.

Alcoholism can be viewed as a motivational disorder that results from alterations in brain systems for ingestive behavior. Therefore, it was hypothesized that alcohol intake might alter the expression of hypothalamic peptides that stimulate feeding. Earlier studies showed that hypothalamic injection of the feeding-stimulatory peptide, galanin (GAL), increases the release of dopamine (DA) in the nucleus accumbens (NAc), as does systemic alcohol, leading to a focus on GAL. Results of this study demonstrate the following: (1). Ethanol, injected daily (0.8 g/kg 10% v/v) for 7 days in male rats, markedly increased the expression of GAL but not of neuropeptide Y (NPY). This occurred in specific hypothalamic nuclei, namely the dorsomedial nucleus (DMN), paraventricular nucleus (PVN) and perifornical lateral hypothalamus (PLH). (2). Rats induced to drink ethanol ad libitum, by gradually increasing the concentration from 1% to 9% v/v without adding sugar or flavoring, exhibited a similar stimulation of GAL mRNA in the PVN and GAL immunoreactivity in the DMN and PVN. (3). Rats given increasing ethanol concentrations, with 12 h access starting 4 h into the dark cycle, had a mean blood alcohol concentration of 18 mg/dl and exhibited a similar increase in GAL expression in the DMN and PVN. (4) Withdrawal from the opioid effects of 9% ethanol, produced by injection of naloxone (3 mg/kg sc), reversed this ethanol effect by significantly reducing GAL expression in the DMN and PLH below baseline levels. These studies suggest a possible role for hypothalamic GAL in alcohol abuse.

Reduced serotonergic immunoreactive fibers in the forebrain of alcohol-preferring rats.

Our previous study indicated that 5-hydroxytryptamine (5-HT) immunoreactive fiber densities were decreased in specific areas of the brain in alcohol-preferring rats (P) when compared with alcohol-nonpreferring rats (NP). The results of our current study show that there are quantitative and qualitative differences in 5-HT innervation in other selected regions of the forebrains of P rats. The 5-HT fiber density in the brains of young adult P and NP rats was measured by immunocytochemistry and quantitative image analysis. A routine error of two-dimensional quantitation of nerve fiber was addressed and an adjustment was made. The amount of 5-HT fibers was significantly lower in CA4 and fasciola cinereum of the dorsal hippocampus, caudate-putamen, and hypothalamus of the P as compared with NP rats (unpaired Student's t tests). In examining the fiber types, we found that, in the frontal cortical and hippocampal regions, where normally fine 5-HT fibers with small varicosities and thick 5-HT fibers with large varicosities coexist, fewer fine 5-HT fibers were seen in P rats as compared with NP rats. The fine fibers are known to be vulnerable to abusive drugs. These observations indicate that (a) there are quantitative differences in 5-HT innervation or that the 5-HT in some 5-HT fibers is reduced to a level undetectable by immunocytochemistry, and (b) the fine 5-HT fibers are specifically reduced to a greater degree in the selected brain regions of P rats when compared with that of NP rats. The involvement of the 5-HT system in the alcohol abuse is discussed.

Influence of dietary zinc on hepatic collagen and prolyl hydroxylase activity in alcoholic rats.

The effects of dietary zinc on hepatic collagen and prolyl hydroxylase activity in normal and alcoholic rats has been investigated in four groups of pair-fed male Wistar rats given either liquid ethanol or a control diet for 12 wk. Each group of pair-fed animals received a diet with a different zinc concentration (standard diet, 7.6 mg/L; low-zinc diet, 3.4 mg/L; zinc-supplemented diet, 76 mg/L; and zinc-extrasupplemented, 300 mg/L. There were no significant differences in hepatic collagen concentration and prolyl hydroxylase activity between alcoholic and normal rats receiving a standard diet (collagen, 77 +/- 5 and 73 +/- 6 micrograms/mg protein; and prolyl hydroxylase; 37 +/- 26 and 36 +/- 22 cpm/mg protein). Alcoholic rats fed a low-zinc diet showed increased prolyl hydroxylase activity (75 +/- 10 cpm/mg protein, p less than 0.05), although no changes in hepatic collagen (77 +/- 10 micrograms/mg protein) were observed in comparison with rats fed a standard alcoholic diet. By contrast, hepatic collagen was significantly lower in alcoholic rats fed a zinc-supplemented diet (66 +/- 4 and 63 +/- 3 micrograms/mg protein, p less than 0.05 and p less than 0.01, respectively), and hepatic prolyl hydroxylase activity was particularly lower in rats receiving zinc 300 mg/L (18 +/- 20 cpm/mg protein). Similar effects were observed in normal rats. We conclude that dietary zinc influences hepatic prolyl hydroxylase activity and collagen deposition in alcoholic rats, and in consequence, the control of dietary zinc is necessary to assess the effects of alcohol on collagen metabolism in rats.