Alcohol Consumption by Young Actively Growing Rats: A Study of Cortical Bone Histomorphometry and Mechanical Properties

Alcohol consumption by young actively growing rats has been previously demonstrated to decrease cortical and cancellous bone density, to reduce trabecular bone volume, and to inhibit bone growth at the epiphyseal growth plate. This study addresses the action of alcohol on cortical bone growth using histomorphometric techniques and on mechanical properties by three-point bending. Four-week-old, female Sprague-Dawley rats were divided into three groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pairfed animals (weight-matched to ethanol rats) received an isocaloric liquid diet in which maltose-dextrin-substituted calories were supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Femora were removed for analysis after 2, 4, 6, or 8 weeks on the diets. Cortical bone area, bone formation rates, and mineral apposition rates were reduced in the alcohol-fed animals. Bone stiffness, strength, and energy absorbed to fracture were significantly lower in the alcohol-fed animals. This distinctive alcohol effect was revealed to be caused by lower quality bone tissue as reflected by lower elastic moduli and yield strengths.     

Effect of Alcohol Consumption on Adult and Aged Bone: A Histomorphometric Study of the Rat Animal Model

The adult and aged skeleton exist in a time when osteoporosis and age-related bone loss is at a maximum, and it is modified by lifestyle factors such as alcohol. To determine the effect of life-long alcohol consumption on the adult and aged rat model, 4-week-old female Sprague-Dawley rats were divided into three diet groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pair-fed animals (weight-matched to ethanol rats) received an isocaloric liquid diet in which maltose-dextrin substituted calories supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Proximal tibiae were removed and prepared for histomorphometric analysis after 3, 6, 9, 12, or 18 months on the diets. Previous studies, with young animals, showed that chronic alcohol consumption during the age of bone development reduced bone volume and trabecular number in cancellous bone. The present study demonstrates that these reductions last throughout life. The rate of bone formation is reduced in alcohol-fed animals, but most bone cell parameters are relative normal, except for wall thickness, indicating a reduced osteoblast activity.     

Alcohol Consumption by Young Actively Growing Rats: A Histomorphometric Study of Cancellous Bone

Alcohol consumption by young actively growing rats has been previously demonstrated to decrease bone density. This study addresses the mechanism of alcohol action on the early phases of bone growth and development using histomorphometric techniques. Four-week-old, female Sprague-Dawley rats were divided into three groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pair-fed animals (weight-matched to ethanol rats) received an isocaloric liquid diet in which maltose-dextrin-substituted calories were supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Proximal tibiae, including epiphyseal growth plate, were removed for analysis after 2,4, 6, or 8 weeks on the diets. Trabecular volume and number were greatly reduced in the alcohol-fed animals; however, bone formation rates and mineralization rates were normal. Epiphyseal growth rate and proliferation rate were essentially stopped in the alcohol-fed animals.     

Effects of Ethanol and Control Liquid Diets on the Hypothalamic-Pituitary-Thyroid Axis of Male Fischer-344 Rats

The effects of a high dextrose liquid diet containing ethanol and two different control liquid diets on serum and brain thyroid axis hormones and liver and brain deiodinase activities were studied in groups of adult male Fischer-344 (F-344) rats. Rats received either lab chow, ad libitum; a nutritionally complete 10% (w/v) ethanol liquid diet, ad libitum; a volume of either a high carbohydrate (HC) or a high fat (HF) isocaloric control liquid diet equal to the volume of diet consumed by rats given the ethanol diet; or the HC control diet, ad libitum. Consumption of liquid diets was measured daily and body weights recorded every other day throughout the study. Hormones were measured after 2, 4, or 8 weeks and deiodinase activities after 4 or 8 weeks. Also, groups of rats were given the 10% ethanol diet, ad libitum, or pair-fed the HC control diet intermittently for 8 weeks, and thyroid hormones and thyroid-stimulating hormone (TSH) response to thyrotropin-releasing hormone (TRH) were determined. Within 2 weeks rats became accustomed to all diets and thereafter weight gain was comparable in all groups. Small differences between serum thyroid hormones of rats fed the ethanol diet and pair-fed HC or HF controls may have been caused by lower T4 secretion in ethanol-fed rats. Marked differences in free and total T4 and T3 between F-344 rats fed liquid diets for 4 or 8 weeks and rats fed lab chow probably resulted from higher liver 5'-deiodinase activity in rats fed liquid diets.(ABSTRACT TRUNCATED AT 250 WORDS)     

Alcohol Protects the Diaphragm during Dietary Restriction

We recently reported that alcoholic rat diaphragm develops greater contractile force than diaphragm of pair-fed control animals. The present experiment examines whether alcohol or dietary restriction is the more likely cause of this surprising finding. We conditioned 10 rats using a liquid diet containing ethanol as 36% of calories. Ten pair-fed control animals received an equal amount of isocaloric, ethanol-free liquid diet. Ten ad libitum control animals had unrestricted access to lab chow and water. Rats were killed after 30 weeks. Left costal diaphragm strips were studied in vitro at optimal length using direct stimulation at supramaximal voltage. Isometric force was measured and divided by muscle cross-section to compute stress. Maximal tetanic stresses developed by muscle from pair-fed controls were systematically less than alcoholic and ad libitum control values (p less than 0.0001); this did not depend on temperature (25 degrees vs. 37 degrees; p greater than 0.50). Pair-feeding increased twitch half-relaxation times (p less than 0.03) and shifted the tetanic stress-stimulation frequency relationship leftward by 10 Hz (p less than 0.01). Diaphragm of pair-fed rats continued to generate lower stresses during the fatigue caused by repeated contractions (p less than 0.01). We conclude that dietary restriction associated with pair-feeding compromises diaphragm performance in rats. Chronic alcohol consumption prevents or reverses these changes, since diaphragm function of alcoholic and ad libitum control animals was not different.     

Alcohol Consumption Inhibits Bone Growth and Development in Young Actively Growing Rats

Adolescence is an age of widespread alcohol abuse, but the effect of alcohol consumption on bone formation has not been studied in the young population. This study addresses the effect of alcohol on the early phases of bone growth and development in an animal model. Four-week-old, female Sprague-Dawley rats were divided into three groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pair-fed animals (weight-matched to ethanol rats) received an iso-caloric liquid diet in which maltose-dextrin substituted calories supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Proximal tibiae (primarily cancellous bone) and femora (primarily cortical bone) were removed for analysis after 2, 4, 6, or 8 weeks on the diets. Serum was collected for analysis of calcium levels, osteocalcin, corticosterone, growth hormone, parathyroid hormone, and 25-hydroxyvitamin D. The most rapid weight gain occurred between 6 and 8 weeks of age, and it was significantly delayed in alcohol and pair-fed animals. Almost all morphological parameters of bone were lower in the alcohol groups. No significant difference in serum calcium levels, osteocalcin, or growth hormone levels were found, and small difference in calciotropic hormone levels was found between groups. The results indicate that chronic alcohol consumption during the age of bone development reduces bone density and peak bone mass in both cortical and cancellous bone. The mechanism whereby this effect occurs is not fully understood, but, our results suggest that the negative impact of alcohol on growing bone is not due to the secondary effects of altered bone mineral regulating hormones.     

Chronic Alcohol Consumption During Male Rat Adolescence Impairs Skeletal Development Through Effects on Osteoblast Gene Expression, Bone Mineral Density, and Bone Strength

BACKGROUND: The effect of chronic alcohol ingestion on bone formation is mediated through its direct actions on osteoblasts. The affected population of mature osteoblasts declines in both number and function resulting in decreased cancellous bone volume and cortical bone strength. Although the mechanism of action on osteoblasts is unknown, alcohol alters osteoblast gene expression and matrix synthesis. METHODS: Male rats consuming alcohol (EtOH) daily for 60 days from 35 days of age until 95 days of age (unrecovered group) were compared to rats switched to a regular diet of rat chow without EtOH for an additional 90 days (recovered group). The effects of chronic dietary EtOH on skeletal development during adolescence were examined in the unrecovered and recovered rats by hormonal analysis, bone mineral density determination, bone histomorphometry, metaphyseal gene expression for osteoblast-specific proteins, and biomechanical analysis. RESULTS: The unrecovered EtOH imbibing rats weighed less than their paired isocaloric-fed and ad libitum mates. Statistically significant reductions occurred in femur lengths in the unrecovered EtOH-fed group compared to controls. Serum testosterone levels were significantly decreased by EtOH consumption but returned to higher normal levels during the recovery period. Serum insulin-like growth factor-1 (IGF-1) levels were unaffected by EtOH. Serum osteocalcin levels in the unrecovered EtOH-fed group were higher than those in the recovered group but EtOH intake did not elevate the unrecovered levels compared to isocaloric or ad libitum control rats. Quantitative computed tomography (QCT) determination of bone mineral density (BMD) revealed a statistically significant reduction only in the distal femur metaphysis in the unrecovered EtOH-fed rats. BMD increased during recovery in the distal femur metaphysis and femur mid-cortex. Image analysis of midsagittal sections of the proximal tibial metaphysis of unrecovered rats revealed reductions in cancellous area, trabecular cellularity and thickness, and increased trabecular separation. Cortical widths were significantly reduced by chronic EtOH consumption. These changes remained statistically significant at the end of the recovery period. Four-point biomechanical testing of femurs from EtOH-fed and control unrecovered groups revealed significant reductions in cortical strength, energy-to-failure, and stiffness. These cortical characteristics returned to normal values with abstinence. Tibial metaphyseal alpha-1 type I collagen and osteocalcin mRNA expression levels were significantly elevated above the paired isocaloric control levels after 60 days of EtOH consumption. Metaphyseal alkaline phosphatase mRNA levels remained unaltered by EtOH consumption in the unrecovered group. After 90 days of abstinence alpha-1 type I collagen and alkaline phosphatase gene expression levels remained significantly elevated over the isocaloric and ad libitum control levels (collagen) and the isocaloric control value (alkaline phosphatase). However, metaphyseal osteocalcin mRNA levels declined to normal levels during abstinence. CONCLUSIONS: Chronic consumption of EtOH during the peripubertal period of skeletal growth leads directly to decreased metaphyseal and cortical bone mediated through effects on osteoblasts. Removal of EtOH from the diet is accompanied by incomplete restoration of normal bone metabolism during skeletal growth.     

Effect of Alcohol Consumption on Adult and Aged Bone: Composition, Morphology, and Hormone Levels of a Rat Animal Model

To determine the effect of life-long alcohol consumption on the adult and aged rat model, 4-week-old, female Sprague-Dawley rats were divided into three diet groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pair-fed animals (weight-matched to ethanol rats) received an isocaloric liquid diet in which maltose-dextrin substituted calories supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Proximal tibiae (primarily cancellous bone) and femora (primarily cortical bone) were removed for analysis after 3, 6, 9, 12, or 18 months on the diets. Serum was collected for analysis of calcium levels, the calcium regulating hormones; parathyroid hormone, 25-hydroxyvitamin D, calcitonin, cor-ticosterone, estradiol, testosterone, and IGF-1. Creatinine, SGOT/ AST, and SGPT/ALT levels were measured to determine kidney and liver integrity. Previous studies, with young animals, showed that chronic alcohol consumption during the age of bone development reduced bone density and bone mass in both cortical and cancellous bone. The present study demonstrates that these reductions last throughout life, whereas morphological values, such as length and diameter, attain control levels. Calcium regulating hormones and sex hormones are essentially normal and do not appear to be the primary causative agent for adult alcohol-induced osteopenia, but it appears to be due to a more direct effect of alcohol on bone cells.     

Aging and dietary modulation of rat skeleton and parathyroid hormone

Studies were carried out on SPF F344 male rats to evaluate the effects of aging and life-prolonging food restriction, without malnutrition, on rat skeleton and circulating PTH. Six-week-old F344 rats were divided into five groups. Group 1 rats were fed ad libitum a diet that contained 21% protein. Group 2 rats were fed 60% of the mean food intake of group 1 rats from 6 weeks of age for the rest of their lives. Group 3 rats were fed 60% of the ad libitum food intake until 6 months of age and then switched to ad libitum feeding. Group 4 rats were fed ad libitum until 6 months of age, and then switched to 60% of the ad libitum food intake. Group 5 rats were fed ad libitum a diet that contained only 12.6% protein so that these animals ingested the same amount of protein per day as the group 2 rats. In group 1 animals, bone length, weight, density, and calcium content increased rapidly with age and plateaued at about 12 months of age. There was no evidence of bone loss in these animals until about 24 months of age, but by 27 months, the animals had lost appreciable amounts of bone. The circulating immunoreactive PTH levels of the animals increased with advancing age, with a marked rise at 27 months. The age-related changes in bone and serum PTH levels of rats in groups 3 and 5 were similar to those of group 1 animals, except that a terminal increase in serum PTH did not occur in group 5 rats. In the groups 2 and 4 animals which were food restricted for the longest period, bone growth and maturation were slowed down, but the animals did not experience senile bone loss or marked terminal increase in circulating PTH. The salutary effects of food restriction were, therefore, not due specifically to the restriction of protein intake or to restricting food intake only during the period of rapid growth.     

Effects of Paternal Alcohol Consumption in Mice

Male mice were divided into four groups, one group was given ad libitum access to a liquid alcohol diet containing 35% ethanol derived calories (EDC). A second group was pair fed an isocaloric control diet containing 17.5% EDC whereas a third was similarly treated with a 0% EDC diet for a minimum of 42 days. A fourth group served as ad libitum nontreated controls to assess the role of pair feeding. Males were then mated with nontreated females. The males consuming alcohol had an increased percentage of abnormal sperm and there was a significant effect of paternal alcohol exposure on implantation sites, but no effect on pre- or postnatal mortality or fetal weight. These results suggest that paternal alcohol consumption adversely affects sperm production but does not affect development of offspring in mice.     

Topiramate moderately reduces the motivation to consume alcohol and has a marked antidepressant effect in rats

Background: In recent human studies, the anticonvulsant drug topiramate (TPM) has shown efficacy in treating alcohol craving and mood disorders. However, preclinical evidence supporting such effects is surprisingly sparse. Three experiments were conducted here to assess possible anticraving and antidepressant effects of TPM using animal models. Methods: In Experiment 1, rats were given 23 weeks ad libitum access to food, water, and either beer (4.44% ethanol v/v) or “near‐beer” (a calorie‐matched nonalcoholic beer, 0.44% ethanol) in their home cages. They were then restricted to daily 1 hour operant sessions in which they licked for water and either beer or near‐beer under a progressive ratio schedule of reinforcement in a lickometer apparatus. The acute effects of TPM on the motivation to consume beer or near‐beer were then assessed. The effects of naloxone were also assessed (as a positive control) after TPM testing. In Experiment 2, rats were given 11 weeks of ad libitum home‐cage access to food, water, and beer. They then received repeated daily injections of TPM and effects on beer consumption under ad libitum home cage access conditions were monitored. In Experiment 3, the effects of TPM were assessed in the modified Porsolt forced swim test, emergence test, and elevated plus‐maze (EPM) using alcohol naïve rats. Results: Topiramate (10, 20, and 40 mg/kg) significantly reduced the motivation to lick for beer, although the maximal effect was moderate in comparison with naloxone (10 mg/kg). However, naloxone, unlike TPM, also reduced responding for near‐beer suggesting an alcohol‐specific effect of TPM. In Experiment 2, TPM (40 and 80 mg/kg) tended to transiently reduce alcohol consumption in the home cage under ad libitum access but this effect disappeared with repeated administration of the drug. TPM (10 to 80 mg/kg, given twice over 4 hours before test) produced a robust dose‐dependent decrease in immobility and increase in active coping strategies in the forced swim test similar to that seen with desipramine (2 × 20 mg/kg). There were modest anxiolytic effects of TPM on the EPM and emergence tests. Conclusions: With acute administration, TPM is moderately effective and relatively selective in reducing the drive to consume alcohol in Wistar rats. This anti‐alcohol effect is modest in comparison with naloxone and appears to dissipate under conditions of chronic treatment and ad libitum alcohol access. A marked antidepressant‐like effect in the forced swim test and partial anxiolytic effects in other animal models suggests that TPM may be a beneficial treatment for affective disorders. These preliminary results suggest further research is warranted to resolve the mechanisms involved in TPM modulation of both mood and alcohol consumption.     

The effects of chronic alcohol consumption and exercise on the skeleton of adult male rats

BACKGROUND: Lifestyle factors are known to affect skeletal development and integrity. Specifically, running has been reported to increase risk of fatigue fractures, whereas chronic alcohol consumption has been shown to reduce bone formation and bone mass. The combined effect of exercise and alcohol on the skeleton has yet to be explored, although alcohol consumption is common among certain physically active populations (e.g., military recruits, college athletes). It was hypothesized that chronic alcohol consumption would accentuate the inherent risk associated with endurance running exercise. METHODS: Six-month-old male Sprague Dawley rats were assigned to one of five groups: baseline, exercise-alcohol diet, exercise-normal diet, sham-alcohol diet, and sham-normal diet. Alcohol-fed rats (35% caloric intake) received a liquid diet ad libitum. Normal animals were pair-fed the identical diet with a maltose dextrin caloric substitute. Exercise was conducted on a motorized treadmill 5 days/wk for 16 weeks. Sham rats were placed on a stationary treadmill for matching time periods. Fluorochrome labels were administered 3 days before baseline and at 10 and 2 days before animals were killed. Heart, soleus, and rectus femoris muscles were wet weighed to assess the effects of training. Tibiae were collected for static and dynamic histomorphometric measurements on cancellous and cortical bone. RESULTS: Muscle weights were larger in the exercised rats versus the sham rats. Alcohol had no significant effect on skeletal muscle weight but did result in larger heart weights in both alcohol-treated groups. Cancellous and periosteal bone formation rates were significantly decreased in the alcohol-fed rats versus rats on the normal diet and were associated with a significant reduction in trabecular thickness in the tibial metaphysis. Cortical and cross-sectional areas were also significantly lower in the alcohol-fed groups compared with the non-alcohol-fed groups. Exercise had no significant effect on cancellous or cortical bone measurements. CONCLUSIONS: Chronic alcohol consumption significantly reduced bone formation. Exercise had no effect on the bone and did not attenuate any of the negative effects of alcohol. The results suggest that alcohol consumption weakens the skeleton and increases the incidence of endurance-exercise-related bone injuries. Thus, individuals who are participating in endurance exercise and consuming alcohol may be at greater risk for exercise-related skeletal injuries. Further investigation of the potential for alcohol to induce detrimental effects on the hearts of individuals participating in endurance exercise is indicated.     

Bone Marrow Triglyceride Accumulation and Hormonal Changes During Long-Term Alcohol Intake in Male and Female Rats

BACKGROUND: Chronic alcohol consumption may influence the metabolism of adipocytes, the most abundant stromal cell phenotype in bone marrow, and promote bone marrow triglyceride accretion. METHODS: Male and female rats 35 days old were fed the Lieber-De Carli liquid diet containing 36% of the calories as alcohol and were compared with pair-fed rats given an isocaloric liquid diet in which maltose-dextrin substituted for the calories supplied by alcohol. Other control rats were fed chow ad libitum. The rats were maintained on these diets for 64 days, after which the femurs were recovered and examined. RESULTS: End weights of male and female alcohol-fed rats were significantly lower than both control groups. Femur diaphyseal bone marrow triglyceride levels were significantly increased in alcohol-fed male and female rats compared with both control groups. Femur bone marrow cavity diameters were significantly increased and cortical thickness was significantly decreased by alcohol in both males and females. Serum insulin levels were significantly decreased by alcohol only in female rats compared with the ad libitum but not the pair-fed control group, and insulin-like growth factor-1 levels were significantly reduced in male and female rats given the alcohol diet compared with both controls. Male testosterone and female estradiol levels remained unchanged. Male estradiol levels were significantly increased by alcohol compared with both controls, and female progesterone levels were significantly reduced by alcohol compared with pair-fed rats. Whereas female leptin levels were unchanged by alcohol, male leptin levels were significantly increased by alcohol compared with pair-fed rats. CONCLUSIONS: Hormonal and growth factor changes during chronic alcohol consumption accompany triglyceride accumulation in diaphyseal bone marrow and may parallel the effects of alcohol on mesenchymal stem cells and the balance between osteogenic and adipogenic lineages and their cellular progenies.     

Modulation of age-related hyperparathyroidism and senile bone loss in Fischer rats by soy protein and food restriction

Studies were carried out to explore the influence of soy protein and food restriction on age-related changes in serum PTH and bone. Three groups of male Fischer 344 rats were studied from 6 weeks of age. Group A rats were fed ad libitum diet A, which has casein as the protein source. Group B rats were fed diet B (with casein as protein source) at 60% of the mean ad libitum food intake. Group C rats were fed ad libitum diet C, which has soy protein as the protein source. The animals were killed at periodic intervals beginning at 6 months of age after an overnight fast. Serum PTH, measured with an intact N-terminal-specific RIA, and immunoreactive calcitonin increased progressively with aging. The increase was markedly suppressed by food restriction, and in the case of PTH by the soy protein diet as well. Serum creatinine started to increase after 18 months of age, and both dietary regimens of groups 2 and 3 retarded the increase. Aging was associated with a fall in serum 25-hydroxyvitamin D, and loss of bone occurred during the terminal part of life in the ad libitum-fed animals. These were prevented by food restriction, while the soy protein diet delayed the onset of bone loss. We conclude from these findings and other data from this study that in the male F344 rats 1) an age-related increase in serum PTH precedes an age-related increase in serum creatinine concentration; 2) an age-related decline in renal function probably contributes to age-related hyperparathyroidism, which, in turn, contributes to senile bone loss; 3) food restriction inhibits age-related hyperparathyroidism and senile bone loss; 4) on the basis of the data from rats fed a soy protein-containing diet, a decline in renal function and progressive hyperparathyroidism are not inevitable consequences of aging in the ad libitum fed rats.     

Effect of chronic alcohol consumption on the pregnant mare serum gonadotropin-induced luteinizing hormone surge

The studies reported in this paper were undertaken to investigate the effect of chronic (10 day) alcohol consumption on female pituitary-gonadal function. The immature female rat model treated with pregnant mare serum gonadotropin (PMSG) was used since it results in a highly reproducible luteinizing hormone (LH) surge and ovulation. Twenty-day-old female rats were placed on diets that were either (1) unrestricted (ad libitum); (2) contained 5% ethanol in a liquid diet, or (3) isocalorically pair-fed with the liquid diet to the ethanol group. After 10 days on their respective diets, the groups were subdivided and given either 8 IU of PMSG in 0.1 ml saline or 0.1 ml saline s.c. between 10.00 and 11.00 h. The animals were sacrificed by decapitation at 24, 48, 52, 54, 56, 58, 60 and 62 h after injection. Trunk blood was obtained for serum measurements of LH. The uteri were weighed and prepared for the histological study. In all dietary groups, serum LH levels were significantly higher in the PMSG-treated animals when compared to the saline controls at all time intervals with the exception of the alcohol 58-hour group. In the ad libitum animals, plasma LH concentrations were highest at 52 h following hormone administration. The serum LH concentrations were highest at 56 h after hormone administration in the pair-fed group and were significantly less than the ad libitum group at 52, 54, 56, and 58 h after PMSG stimulation. No significant plasma LH surge was observed in the alcohol group and the LH concentrations were significantly less than the pair-fed rats at 56 and 58 h after PMSG treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of Exposure to an Alcohol Diet for 10 Days on the Ability of Interleukin-1β to Release ACTH and Corticosterone in the Adult Ovariectomized Female Rat

Adult ovariectomized female rats were fed an alcohol diet for 10 days. Animals fed ad libitum, or fed an isocaloric diet (pair-fed), were also included in all experiments. The intravenous injection of interleukin-β caused dose-related increases in plasma adrenocorticotropic hormone (ACTH) levels in all three groups of rats. However, alcohol-fed animals showed a significant blunting of their ACTH, but not corticosterone response, in comparison with rats fed ad libitum or pair-fed. In contrast, corticotropin-releasing factor (CRF) injection caused overall statistically comparable ACTH secretory rates in all animals, although small differences were observed in some cases. Exposure to mild electroshocks for 30 min significantly increased ACTH values in all animals, but alcohol-fed rats again showed blunted release. In this paradigm, pair-fed animals exhibited a response that was intermediate between that of the ad libitum and alcohol-fed groups.
We conclude that chronic alcohol consumption decreases the response of the hypothalamic-pituitary axis to cytokines and mild footshocks. This suggests that the activity of both CRF nerve terminals in the median eminence, and of CRF perikarya in the hypothalamus, is inhibited by this treatment, although pituitary responsiveness to CRF appears unchanged.     

Sex Differences in Alcohol Preference and Drinking Patterns Emerge during the Early Postpubertal Period in Sprague-Dawley Rats

Young male and female Sprague-Dawley rats (30 days old) were assigned randomly to three treatment groups: (1) alcohol treatment—received beer with 5% ethanol added, food, and water ad libitum; (2) pair-fed treatment—received nonalcoholic beer plus sucrose and food to match intake by the alcohol-treated animals; and (3) control treatment—received food and water ad libitum. Animals were tested for alcohol preference for 24 hr and then received their assigned treatments for a period of 30 days, followed by a period of abstinence before alcohol preference testing again at 74 days of age. Males given free access to beer and water did not drink large quantities of beer. Females given free access to beer and water drank a lot of beer on the first day, but decreased intake until ˜52 days of age. A developmental change in young female rats at ˜52 days of age resulted in increased voluntary ethanol intake, possibly caused by hormonal changes associated with the establishment of estrous cycles. When the animals were tested for alcohol preference at 74 days of age after a period of abstinence, males and females in the pair-fed group had greater alcohol preference than animals in the other groups. Females in the pair-fed group had greater alcohol intake based on body weight than males in the pair-fed group and males and females in all other groups. These results provide insight into sex differences in the development of voluntary drinking behavior and responses of drinking behavior to the early stress of pair-feeding.     

Restricted diet rescues rat enteric motor neurones from age related cell death

BACKGROUND: Alone among autonomic neurones, enteric neurones are known to be vulnerable to age related cell death; over 50% may be lost in aging rodents. A previous study demonstrated unexpectedly that neurones of the myenteric plexus from rats fed a restricted diet appeared not to suffer from extensive cell death in contrast with previous studies of ad libitum fed animals. AIMS: To compare myenteric neurone numbers in the ileum of young and aging male Sprague-Dawley rats fed either ad libitum or a restricted diet. METHODS: Neurones were counted in whole mount preparations of rat ileum stained immunohistochemically for the pan-neuronal marker PGP9.5, for choline acetyltransferase, or for nitric oxide synthase, or with NADH or NADPH histochemistry. RESULTS: Neurone numbers in the rat myenteric plexus were substantially affected by the dietary regimen: ad libitum feeding (50-60 g per day of standard rat chow) resulted in the death of about 50% of myenteric neurones in 24 month Sprague-Dawley rats, while numbers were unchanged when the daily dietary intake was halved between the ages of six and 24 months. Animals fed a double restricted diet (15 g per day) showed no cell loss at 30 months, as well as the predicted increase in longevity. Neurone loss was largely complete by 16 months in ad libitum fed animals. Numbers of cholinergic (possibly motor) neurones, as demonstrated by choline acetyltransferase immunohistochemistry, were substantially reduced in ad libitum fed aging rats but not in animals fed a restricted diet. Loss of cholinergic neurones after ad libitum feeding was confirmed by reduced numbers of neurones of a size range matching that of cholinergic neurones. CONCLUSIONS: Ad libitum feeding of adult rats has adverse effects on the survival of myenteric neurones, neurone loss commencing before 16 months of age. Cholinergic neurones appear to be particularly vulnerable to the effects of diet. Restricting dietary intake from six months of age prevents neurone loss almost entirely up to 30 months of age in these rats.     

Alcohol-induced chronic pancreatitis in rats after temporary occlusion of biliopancreatic ducts with Ethibloc

Chronic obstructive pancreatitis-like histological and biochemical alterations were provoked in male Wistar rats with Ethibloc occlusion of the common bile duct and the main pancreatic ducts. After the disappearance of the glue from the ducts, a gradual and almost total recovery was demonstrated during a 2-month observation period. About 12 g/kg of alcohol (20% vol/vol) given daily by gastric intubation and ad libitum intake inhibited the recovery of pancreatic weight and enzyme contents in the occluded rats, and within a 2-month period chronic calcifying-type pancreatitis became evident with some signs of remaining obstructive pancreatitis-like lesions. Cessation of alcohol administration after 2 months resulted in a recovery of pancreatic weight and enzyme contents, although morphological regeneration was less pronounced and calcification remained visible in some rats. A 50% raw soy flour diet provoked some further changes in the proportion of enzymes without any supplementary increases of pancreatic weight and protein content. This animal model of chronic pancreatitis demonstrates that chronic obstructive and calcifying pancreatitis can appear together and earlier if the etiological factors act in combination. Suppression of pancreatic regeneration by alcohol seems to be necessary to maintain chronic pancreatitis-like lesions and to develop calcification.     

Effect of chronic feeding of ethanol diet of “average” fat content on rat pancreas

The present study was done to determine the influence of dietary fat on the effect of ethanol on pancreatic macromolecular content and secretion. Weight-matched groups of Sprague-Dawley rats were divided into controls fed Rodent-Blox ad libitum; American Institute of Nutrition-76 (AIN-76) diet containing 12% calories as fat with 36% of carbohydrate calories replaced with 5% (weight/volume) concentration of ethanol fed ad libitum pair fed with animals given isocaloric amounts of AIN-76 diet for three to six months. Compared with Rodent-Blox fed controls, tissue content of trypsinogen, chymotrypsinogen, amylase, and lipase; specific activity and concentration of trypsinogen, chymotrypsinogen; and concentration of amylase were decreased at six months in AIN-76 fed controls. These changes did not result from diminished food intake, but were due to adaptation to the liquid diet. Animals fed AIN-76 diet plus ethanol did not show significant difference in the total content, specific activity, concentration, and secretion of digestive enzymes compared with those animals pair fed isocaloric amounts of AIN-76 diet. Activation of trypsinogen by exogenous trypsin was lower in rats fed AIN-76 diet and a similar change was observed in animals fed AIN-76 diet with ethanol for six months. These findings are in contrast to increased secretion of proteases and decreased trypsin inhibitor observed previously in animals fed ethanol in a diet containing "high" fat. These data indicate that ethanol effect on the pancreas is modified by dietary intake of fat and/or carbohydrates.