Ethanol-insulin interrelationships in the rat studied in vitro and in vivo: evidence for direct ethanol inhibition of biphasic glucose-induced insulin secretion

Associations of smoking and alcohol consumption with impaired β-cell function in Chinese men

BACKGROUND

The aims of the present study were to examine the association of cigarette smoking and alcohol consumption with impaired β-cell function in Chinese men, particularly the interaction of smoking and alcohol consumption on impaired insulin secretion.

METHODS

A population-based cross-sectional study was performed in 3957 Chinese men aged ≥40 years. The homeostatic model assessment of β-cell function (HOMA-β) was calculated, and impaired β-cell function was defined as less than the lowest quartile HOMA-βcut-off point.

RESULTS

The prevalence of impaired β-cell function in current smokers and heavy drinkers (≥200 g/week) was significantly higher than in non-smokers and non-drinkers, respectively. Compared with non-smoking, current smoking had an exacerbating relationship with impaired β-cell function (odds ratio [OR] 1.78; 95% confidence interval [CI] 1.47-2.15; P < 0.001). No significant association was found between impaired β-cell function and former smoking (P = 0.21), although low and heavy drinking were associated with an increased risk of impaired β-cell function (OR 1.40 [95% CI 1.07-1.81] and 2.14 [95% CI 1.77-2.58], respectively) compared with non-drinking. The combination of current smoking and heavy drinking was associated with the highest risk of impaired β-cell function (OR 3.16; 95% CI 2.43-4.12; P < 0.0001) after adjustment for confounders. We did not detect an additive interaction between current smoking and heavy drinking on the association with impaired β-cell function.

CONCLUSIONS

Cigarette smoking and alcohol consumption were significantly and independently associated with impaired β-cell function in Chinese men.

Impact of Alcohol on Glycemic Control and Insulin Action

Alcohol has profound effects on tissue and whole-body fuel metabolism which contribute to the increased morbidity and mortality in individuals with alcohol use disorder. This review focuses on the glucose metabolic effects of alcohol, primarily in the muscle, liver and adipose tissue, under basal postabsorptive conditions and in response to insulin stimulation. While there is a relatively extensive literature in this area, results are often discordant and extrapolating between models and tissues is fraught with uncertainty. Comparisons between data generated in experimental cell and animals systems will be contrasted with that obtained from human subjects as often times results differ. Further, the nutritional status is also an important component of the sometimes divergent findings pertaining to the effects of alcohol on the regulation of insulin and glucose metabolism. This work is relevant as the contribution of alcohol intake to the development or exacerbation of type 2 diabetes remains ill-defined and a multi-systems approach is likely needed as both alcohol and diabetes affect multiple targets within the body.

Absence of perilipin 2 prevents hepatic steatosis, glucose intolerance and ceramide accumulation in alcohol-fed mice

BACKGROUND

Perilipin 2 (Plin2) is a lipid droplet protein that has roles in both lipid and glucose homeostasis. An increase in Plin2 in liver is associated with the development of steatosis, glucose intolerance, and ceramide accumulation in alcoholic liver disease. We investigated the role of Plin2 on energy balance and glucose and lipid homeostasis in wildtype and Plin2 knockout (Plin2KO) mice chronically fed a Lieber-DeCarli liquid ethanol or control diet for six weeks.

METHODS

We performed in vivo measurements of energy intake and expenditure; body composition; and glucose tolerance. After sacrifice, liver was dissected for histology and lipid analysis.

RESULTS

We found that neither genotype nor diet had a significant effect on final weight, body composition, or energy intake between WT and Plin2KO mice fed alcohol or control diets. Additionally, alcohol feeding did not affect oxygen consumption or carbon dioxide production in Plin2KO mice. We performed glucose tolerance testing and observed that alcohol feeding failed to impair glucose tolerance in Plin2KO mice. Most notably, absence of Plin2 prevented hepatic steatosis and ceramide accumulation in alcohol-fed mice. These changes were related to downregulation of genes involved in lipogenesis and triglyceride synthesis.

CONCLUSIONS

Plin2KO mice chronically fed alcohol are protected from hepatic steatosis, glucose intolerance, and hepatic ceramide accumulation, suggesting a critical pathogenic role of Plin2 in experimental alcoholic liver disease.

Alcohol consumption and higher incidence of impaired fasting glucose or type 2 diabetes in obese Korean men

It is inconclusive whether moderate alcohol consumption reduces the diabetes risk. We observed the development of impaired fasting glucose or type 2 diabetes according to the amount of alcohol intake and body mass index. The annual health evaluation data of 2,500 male workers from 2002 to 2006 were reviewed retrospectively deleting personal identification code. The information contained sex, age, medical history, smoking status, alcohol consumption, participating regular exercise, anthropometric, and biochemistry measurement. Impaired fasting glucose or diabetes was determined when fasting plasma glucose was > or =100mg/dL. Thousand seven hundred seven subjects were eligible after excluding medical history of diabetes or fasting glucose > or =100mg/dL at baseline. The relative risks of its development in group of taking 1-14, 15-29, and > or =30.0g ethanol were 0.842 (95% confidence interval [CI], 0.603-1.176), 1.068 (95% CI, 0.736-1.551), and 1.019 (95% CI, 0.662-1.568) within normal weight group, 1.164 (95% CI, 0.795-1.705), 1.421 (95% CI, 0.947-2.133), and 1.604 (95% CI, 1.031-2.495) within overweight group, and 1.498 (95% CI, 1.042-2.153), 1.634 (95% CI, 1.091-2.447), and 1.563 (95% CI, 1.019-2.396) within obese group each after adjusting age, family history of diabetes, smoking, exercise, serum fasting glucose, aspartate aminotransferase, and gamma-glutamyltransferase with nondrinkers as a reference group. Not only high alcohol consumption but also moderate drinking was related with higher incidence of impaired fasting glucose or diabetes in obese Korean men.

Chronic ethanol and triglyceride turnover in white adipose tissue in rats: inhibition of the anti-lipolytic action of insulin after chronic ethanol contributes to increased triglyceride degradation

Chronic ethanol consumption disrupts whole-body lipid metabolism. Here we tested the hypothesis that regulation of triglyceride homeostasis in adipose tissue is vulnerable to long-term ethanol exposure. After chronic ethanol feeding, total body fat content as well as the quantity of epididymal adipose tissue of male Wistar rats was decreased compared with pair-fed controls. Integrated rates of in vivo triglyceride turnover in epididymal adipose tissue were measured using (2)H(2)O as a tracer. Triglyceride turnover in adipose tissue was increased due to a 2.3-fold increase in triglyceride degradation in ethanol-fed rats compared with pair-fed controls with no effect of ethanol on triglyceride synthesis. Because increased lipolysis accompanied by the release of free fatty acids into the circulation is associated with insulin resistance and liver injury, we focused on determining the mechanisms for increased lipolysis in adipose tissue after chronic ethanol feeding. Chronic ethanol feeding suppressed beta-adrenergic receptor-stimulated lipolysis in both in vivo and ex vivo assays; thus, enhanced triglyceride degradation during ethanol feeding was not due to increased beta-adrenergic-mediated lipolysis. Instead, chronic ethanol feeding markedly impaired insulin-mediated suppression of lipolysis in conscious rats during a hyperinsulinemic-euglycemic clamp as well as in adipocytes isolated from epididymal and subcutaneous adipose tissue. These data demonstrate for the first time that chronic ethanol feeding increased the rate of triglyceride degradation in adipose tissue. Furthermore, this enhanced rate of lipolysis was due to a suppression of the anti-lipolytic effects of insulin in adipocytes after chronic ethanol feeding.

Chronic ethanol-induced insulin resistance is associated with macrophage infiltration into adipose tissue and altered expression of adipocytokines

BACKGROUND

Chronic ethanol consumption disrupts glucose homeostasis and is associated with the development of insulin resistance. While adipose tissue and skeletal muscle are the two major organs utilizing glucose in response to insulin, the relative contribution of these two tissues to impaired glucose homeostasis during chronic ethanol feeding is not known. As other models of insulin resistance, such as obesity, are characterized by an infiltration of macrophages into adipose tissue, as well as changes in the expression of adipocytokines that play a central role in the regulation of insulin sensitivity, we hypothesized that chronic ethanol-induced insulin resistance would be associated with increased macrophage infiltration into adipose tissue and changes in the expression of adipocytokines by adipose tissue.

METHODS

Male Wistar rats were fed a liquid diet containing ethanol as 36% of calories or pair-fed a control diet for 4 weeks. The effects of chronic ethanol feeding on insulin-stimulated glucose utilization were studied using the hyperinsulinemic-euglycemic clamp technique, coupled with the use of isotopic tracers. Further, macrophage infiltration into adipose tissue and expression of adipocytokines were also assessed after chronic ethanol feeding.

RESULTS

Hyperinsulinemic-euglycemic clamp studies revealed that chronic ethanol feeding to rats decreased whole-body glucose utilization and decreased insulin-mediated suppression of hepatic glucose production. Chronic ethanol feeding decreased glucose uptake in epididymal, subcutaneous, and omental adipose tissue during the hyperinsulinemic-euglycemic clamp, but had no effect on glucose disposal in skeletal muscle. Chronic ethanol feeding increased the infiltration of macrophages into epididymal adipose tissue and changed the expression of mRNA for adipocytokines: expression of mRNA for monocyte chemoattractant protein 1, tumor necrosis factor alpha, and interleukin-6 were increased, while expression of mRNA for retinol binding protein 4 and adiponectin were decreased in epididymal adipose tissue.

CONCLUSIONS

These data demonstrate that chronic ethanol feeding results in the development of insulin resistance, associated with impaired insulin-mediated suppression of hepatic glucose production and decreased insulin-stimulated glucose uptake into adipose tissue. Chronic ethanol-induced insulin resistance was associated with increased macrophage infiltration into adipose tissue, as well as changes in the expression of adipocytokines by adipose tissue.

Relation of alcohol use and smoking to glucose tolerance status in Japanese men

To investigate the relation of alcohol use and cigarette smoking to glucose tolerance status, we performed a cross-sectional study of 3038 male officials aged 46-59 years in the Self-Defense Forces. Glucose tolerance status was determined by a 75-g oral glucose tolerance test. A self-administered questionnaire was used to ascertain alcohol use, smoking habits, and other lifestyle characteristics. Statistical adjustment was made for parental history of diabetes, body mass index, and leisure-time physical activity. Alcohol use was positively associated with impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes mellitus each. The association was dose-dependent, with odds of each category of glucose intolerance increased even among those with moderate alcohol use. Cigarette smoking was not related to any categories of glucose intolerance. Alcohol use may confer increased risks not only of type 2 diabetes mellitus but also of preceding glucose intolerance status. Smoking does not seem to deteriorate glucose tolerance.

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Aldehyde dehydrogenase 2 and beta3-adrenergic receptor gene polymorphisms: their association with elevated liver enzymes and metabolic syndrome

Recent studies indicate that some patients with nonalcoholic fatty liver have ongoing liver injury that may progress from steatosis to steatohepatitis or fibrosis. The present study was designed to clarify the clinical features of liver dysfunction observed in the course of workplace physical check-ups in relation to multiple risk factor syndrome including obesity, hyperlipidemia, hypertension, and impaired glucose tolerance, and to clarify the involvement of aldehyde dehydrogenase 2 (ALDH2) and beta(3)-adrenergic receptor (beta3-AR) gene polymorphisms in elevation of liver enzymes. One hundred forty-eight male workers 35 years of age were enrolled. They were requested to answer questionnaires about drinking and smoking habits, and underwent urinalysis, physical and peripheral blood examinations, blood chemistry, electrocardiogram and chest x-rays. The genotypes of ALDH2 and beta3-AR were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The subjects were divided into active ALDH2 or inactive ALDH2 groups. They were also divided into 2 groups according to the beta3-AR genotype. The relationships between ALDH2 and beta3-AR gene polymorphism and the results of the physical examination including liver function tests were analyzed. The subjects were also divided according to the number of components of metabolic syndrome. The prevalence of elevated alanine aminotransferase (ALT) level increased with the accumulation of components of metabolic syndrome. Active ALDH2 was associated with elevated ALT level to a greater degree than beta3-AR polymorphism. Among those with normal body mass index (BMI), the genotypes of ALDH2 and beta3-AR were strongly associated with elevated ALT level. Logistic regression analysis revealed that BMI, triglyceride level, and ALDH2 genotype were associated with ALT elevation. In conclusion, evaluating the genotype of ALDH2 and beta3-AR may assist in predicting and preventing the development of fatty liver which may be related to multiple risk factor syndrome.

Alcohol consumption and risk for development of impaired fasting glucose or type 2 diabetes in middle-aged Japanese men

OBJECTIVE

To investigate the association between alcohol consumption and risk for development of diabetes.

RESEARCH DESIGN AND METHODS

We examined 2,953 Japanese male office workers aged 35-59 years who did not have impaired fasting glucose (IFG) (a fasting plasma glucose concentration of 6.1-6.9 mmol/l), type 2 diabetes (a fasting plasma glucose concentration of > or =7.0 mmol/l or receipt of hypoglycemic medication), medication for hypertension, or a history of cardiovascular disease. Fasting plasma glucose concentrations were measured at periodic annual health examinations from May 1994 through May 2001.

RESULTS

There was a U-shaped association between alcohol consumption and the incidence of IFG or type 2 diabetes during 7 years of follow-up, with the lowest incidence at alcohol intake of 23.0-45.9 g ethanol/day. After controlling for age, family history of diabetes, BMI, cigarette smoking, and physical activity, the relative risk for development of IFG or type 2 diabetes compared with alcohol consumption of 23.0-45.9 g ethanol/day was 1.51 (95% CI, 1.07-2.13), 1.31 (95% CI, 0.93-1.84), 1.18 (95% CI, 0.87-1.61), and 1.43 (95% CI, 1.01-2.02) with alcohol consumption of 0, 0.1-22.9, 46.0-68.9, and > or =69.0 g ethanol/day, respectively (P for quadratic trend = 0.016). Analyses by presence or absence of a risk factor revealed that a U-shaped association was more evident in older men, men without a family history of diabetes, and nonsmokers.

CONCLUSIONS

These results indicate that moderate alcohol consumption among apparently healthy Japanese men is associated with reduced risk for development of IFG or type 2 diabetes.

Ethanol decreases basal insulin secretion from HIT-T15 cells

Various epidemiological studies suggest that alcohol intake is one of the risk factors leading to type II or non-insulin-dependent diabetes mellitus (NIDDM), but the effect of alcohol on beta-cell function remains unexplored. To study the mechanism of the diabetogenic action of ethanol, we investigated the effect of ethanol on beta-cell functions using a single clonal beta-cell line, HIT-T15 cells. When HIT cells were treated with ethanol, the metabolic activity judged by MTT assay was inhibited in dose- and time dependent manners, but cytotoxicity was not observed. Ethanol also inhibited basal insulin secretion by 30% compared to the untreated control. However, glucose-stimulated insulin secretion was not impaired by ethanol although the basal insulin secretion was inhibited. These results imply that ethanol exert beta-cells to overwork in order to compensate inhibition of the basal secretion. This finding may at least in part explain the diabetogenic action of ethanol.

Four-week ethanol drinking increases both thyrotropin-releasing hormone (TRH) release and content in rat pancreatic islets

Ethanol exerts profound effects on the endocrine and exocrine pancreas. Some effects of chronic alcohol consumption on insulin secretion in response to glucose load are similar to those of TRH gene disruption. TRH is present in insulin-producing B-cells of the islets of Langerhans; its role in this location is still not fully explored. To examine the possible effect of long-term in vivo ethanol treatment on pancreatic TRH we compared three groups of rats: a 10% (wt:vol) ethanol-drinking group (E), absolute controls (AC) and pair-fed (PF) group with solid food intake corresponding to that of E. The fluidity of pancreatic membranes was not affected by chronic in vivo exposure of rats to ethanol, but was significantly decreased in PF group. Four-week treatment resulted in significantly higher TRH content in isolated islets of the E group and increased basal and 80 mM isotonic ethanol-induced secretion compared to AC and PF. Plasma levels of insulin, C-peptide, IGF-I, and glycemia were, however, not affected by ethanol treatment. Cell swelling, which can be induced by the presence of permeants (e.g. ethanol) in an isotonic extracellular medium, is a strong stimulus for secretion in various types of cells. In the present study, isosmotic ethanol (40, 80, and 160 mM) induced dose-dependent release of TRH and insulin from adult rat pancreatic islets in vitro. The same concentrations were not effective when applied in a hyperosmotic medium (addition of ethanol directly to the medium), thus indicating the participation of cell swelling in the ethanol-induced secretion. In conclusion, chronic ethanol treatment significantly affected pancreatic TRH and this effect might be mediated by cell swelling. The role of these changes in the profound effect of ethanol on the endocrine and exocrine pancreas remains to be established.

Effect of different times of administration of a single ethanol dose on insulin action, insulin secretion and redox state

AIMS

Ethanol (EtOH) can affect glucose metabolism by altering the redox state, insulin-mediated glucose uptake and insulin secretion. We sought to determine the effects of an acute oral EtOH load on insulin secretion and glucose tolerance and the importance of a different timing of administration relative to a glucose load.

METHODS

Eleven subjects underwent a frequently sampled intravenous glucose tolerance test (FSIGT) on three occasions in random order. In one, EtOH was given 50 min 'before' the FSIGT; on the second, the same amount was administered 6 min after the glucose pulse ('during' study); on the third no EtOH was given.

RESULTS

Blood EtOH peaked at 4.43+/-0.24 mmol/l (mean +/- SD) in the 'during' and 4.16+/-0.31 mmol/l in the 'before' study. No differences were noticed in S(I), the index of insulin sensitivity, or in S(G), the glucose effectiveness, between the 'before', 'during' and control studies. There were no differences in the first-phase insulin secretion between the three studies but a significant increase in the sensitivity to glucose of second-phase dynamic insulin response, phi2, in the 'before' (0.062+/-0.036 pmol x min(-2) x (mg(-1) x dl(-1))(-1)) and 'during' (0.063+/-0.059) studies, compared to the control study (0.017+/-0.010, P<0.05) was observed. No differences were observed in the hepatic extraction of insulin. In the 'before' study, there was a significant decline in NEFA (non-esterified fatty acid) concentration from the baseline (mean 602+/-51 micromol/l) to the O min value (mean 353+/-37, P<0.01). During the FSIGT, the mean plasma NEFA concentration was significantly lower in the 'before' and in the 'during' than in the control study.

CONCLUSION

An acute oral EtOH load does not impair glucose metabolism, at least in part because of an increased second-phase insulin secretion. Since this effect is observed irrespective of whether EtOH is consumed either before or during the glucose load, the existence of a priming effect is questioned.

Chronic ethanol feeding impairs glucose tolerance but does not produce skeletal muscle insulin resistance in rat epitrochlearis muscle

Herein, we have investigated whether male Wistar rats develop impaired glucose tolerance after ethanol feeding. Rats were fed a liquid diet providing 35% calories from ethanol (EF) or a control diet that isocalorically replaced ethanol with maltose-dextrins for 4 weeks. Intravenous glucose tolerance was impaired in EF rats compared with pair-fed (PF), but not ad libitum (AL) controls. Areas under the intravenous glucose tolerance test curve were 5476 +/- 516 mm2, 3056 +/- 421 mm2, and 4199 +/- 613 mm2 (p < 0.05) for AL, PF, and EF rats, respectively. Initial plasma insulin concentrations in EF rats were comparable with PF rats; however, 15 min after a dextrose challenge, plasma insulin levels in EF rats were 39% lower than PF rats. Because skeletal muscle is the primary sink for insulin-mediated glucose disposal, the development of skeletal muscle insulin resistance after ethanol feeding could contribute to impaired glucose tolerance. Total GLUT1 was not affected by diet in either red or white muscle. No difference in the total quantity of insulin-responsive glucose transporter, GLUT4, was observed in red muscle. In contrast, GLUT4 was 20% lower in white muscle from EF rats, compared with PF and AL rats. However, insulin-stimulated glucose transport into the epitrochlearis, a white muscle group, was not impaired with ethanol feeding. These data demonstrate that chronic ethanol feeding impairs glucose tolerance; impaired glucose tolerance was associated with an inability to maintain plasma insulin levels, rather than the development of skeletal muscle insulin resistance.

Effects of chronic alcohol intake on carbohydrate and lipid metabolism in subjects with type II (non-insulin-dependent) diabetes

PURPOSE

To study the effects of chronic alcohol intake on carbohydrate and lipid metabolism in subjects with non-insulin-dependent (type II) diabetes (NIDDM). To also evaluate the effect of alcohol withdrawal on metabolic control.

PATIENTS AND METHODS

The study group consisted of 46 alcohol-consuming patients with NIDDM (NIDDM-B group), 35 non-alcohol-consuming patients with NIDDM (NIDDM group), and 40 normal control subjects. All patients were admitted to the hospital. Carbohydrate and lipid metabolism was assessed in these individuals immediately on admission to the hospital and during the following days.

RESULTS

In the NIDDM-B group, blood alcohol (ethyl alcohol) concentration was very low. However, chronic alcohol intake was associated with higher fasting and postprandial glucose concentrations and higher hemoglobin A1c. No significant differences were found in C-peptide levels. Moreover, higher concentrations of 3-hydroxybutyrate and free fatty acids were observed in the NIDDM-B group than in the NIDDM group. No differences were found in triglyceride concentrations, acid-base patterns, or electrolyte levels. The metabolic effects of alcohol completely waned after 3 days of complete withdrawal.

CONCLUSION

Chronic alcohol intake causes deterioration in metabolic control of persons with NIDDM. The effects induced by alcohol are completely reversed after a few days of withdrawal. Strict metabolic assessment is necessary when alcohol is an important constituent of the diet.

The effect of ethanol infusion on the altered glucose turnover during bacterial infection

The increased glucose turnover seen during the hypermetabolic, hyperdynamic phase of sepsis is part of the body's defense mechanisms. In contrast, the metabolism of ethanol (ETOH) is known to compromise hepatic gluconeogenesis under certain conditions. This study tested the hypothesis that acute infusion of ETOH inhibits the elevated glucose production that is manifested during infection and thereby alters the normal responses to sepsis. In catheterized conscious rats, ETOH or saline infusion was started 24 hours before the induction of sepsis, and continued throughout the experiment. In vivo glucose kinetics were assessed by the infusion of [6-3H, U-14C]-glucose 24 hours after the induction of sepsis. The characteristic sepsis-induced hyperthermia was prevented in ETOH-infused animals. Sepsis increased the plasma lactate concentration (100%), as well as the rates of glucose appearance ([Ra] 77%), recycling (213%), and metabolic clearance ([MCR] 82%) in saline-infused control animals. In contrast, ETOH infusion prevented the sepsis-induced increase in glucose Ra and markedly attenuated the increase in plasma lactate (49%) and glucose recycling (97%). The infusion of ETOH increased the lactate/pyruvate and beta-hydroxybutyrate (BHBA)/acetoacetate (AcAc) ratio in both septic and nonseptic rats. These results indicate that ETOH administration attenuates the increased glucose production, utilization, and elevated arterial lactate, and prevents the hyperthermic response seen during the hypermetabolic phase of sepsis. Thus, ethanol intoxication alters the normal metabolic responses to sepsis, thereby contributing to the compromised host defenses against the challenging bacteria.

Effects of ethanol in acute carbon monoxide poisoning

The combined effects of ethyl alcohol (ETOH) intoxication and carbon monoxide (CO) poisoning were studied in the Levine-prepared rat. Infusion or injection of ETOH before and during 90 min of CO exposure to blood levels 2-4 times those considered legally drunk in humans, increased survival at 2400 ppm, and extended the tolerance time at 2400 ppm and 3000 ppm. CO exposure produced the usual hypothermia, hypotension and hemoconcentration; these responses were not altered by concurrent ETOH treatment. Blood ETOH concentration was increased in the presence of CO, and this was related to CO concentration. Although ETOH did not alter the average degree of hypoglycemia seen during the later stages of CO exposure, rats with the highest ETOH concentration tended to have the lowest blood glucose. ETOH increased the magnitude of the hyperglycemic rebound during recovery from exposure to both CO concentrations. Moreover, the magnitude of the recovery hyperglycemic rebound was directly related to the magnitude of the previous hypoglycemia, at both CO concentrations, with or without ETOH. Rats dying during exposure to both CO concentrations were severely hypoglycemic, whereas survivors maintained more or less normal blood glucose concentrations. The results suggest that the presence of ETOH during CO poisoning increases blood ETOH to higher than expected levels and provides a significant degree of survival protection.

Ethanol administration diminishes the endotoxin-induced increase in glucose metabolism

The metabolism of ethanol (ETOH) is known to increase the cytosolic NADH/NAD ratio and consequently impairs hepatic glucose output in the fasted state. In contrast, one of the characteristic alterations in glucose metabolism produced by the administration of endotoxin is an increase in the de novo synthesis of glucose. Therefore, the present study tests the hypothesis that the acute administration of ETOH will prevent the endotoxin-induced increase in glucose production. In vivo glucose kinetics were determined by the infusion of [6-3H, U-14C]glucose in catheterized conscious rats. The intravenous infusion of tracer glucose, and ETOH (100 mg/100 g b.w./hr) or saline were started at the same time and both continued throughout the experiment. Two hours later the ETOH infusion rate was decreased to maintain the blood ETOH levels between 100 and 160 mg/dl. At 140 min, endotoxin (100 micrograms/100 g b.w.) was injected. ETOH alone did not alter basal values of plasma glucose (5 mM), glucose rate of appearance (Ra; 35 mumols/min/kg) or metabolic clearance (MCR; 7 ml/min/kg). Endotoxin alone increased plasma glucose (80%) and lactate (140%) concentrations, glucose Ra (60%) and recycling (40%) in saline-infused rats, whereas in ETOH-infused animals, plasma glucose and lactate levels were only elevated 40% and glucose Ra and recycling were unchanged. The results show that acute ETOH administration diminishes the increased glucose production and utilization seen in endotoxemia. The attenuation of the endotoxin effect by ethanol is due to inhibition of hepatic glucose production and peripheral glucose utilization.

Ethanol influence on calcium uptake and insulin release by rat islets

Effect of acute ethanol treatment on simultaneous 45Ca++ uptake and insulin response to glucose was measured in isolated rat pancreatic islets. Ethanol, given ip 1 gm/Kg 1 h prior to sacrifice of the animal, decreased significantly 45Ca++ uptake and insulin response to 8.3 and 16.7 mM glucose. Addition of ethanol to the incubation media inhibited 45Ca++ uptake and insulin release in a dose-related matter. Ionophore A23187, which is known to enhance 45Ca++ efflux, decreased 45Ca++ uptake without affecting insulin release. Inhibitory effects of ethanol and ionophore A23187 were not additive when islets were exposed to both test substances simultaneously. Forskolin, an activator of the adenylate cyclase system potentiated the glucose mediated insulin response in rat islets. However, ethanol decreased the insulin response of islets exposed to glucose and forskolin. The data show that ethanol inhibits 45Ca++ uptake response to glucose and that ethanol influence on insulin release may involve a site beyond the formation of cyclic AMP in the process of excitation-secretion coupling.

The effect of ethanol on prolactin secretion in vitro

In order to investigate the action of ethanol on the anterior pituitary gland, the effect of ethanol on prolactin secretion in vitro was studied. Ethanol significantly increased the in vitro incorporation of 3H-leucine into both prolactin contained within the pituitary gland and that released into the medium. The enhancement of 3H labelled-prolactin synthesis induced by ethanol was suppressed by cycloheximide. These results support the hypothesis that ethanol stimulates the in vitro synthesis and release of prolactin by the pituitary gland.

Metabolic acidosis in the alcoholic: a pathophysiologic approach

The purpose of this paper is to review the acid-base abnormalities in patients presenting with metabolic acidosis due to acute ethanol ingestion and to review the theoretical constraints on ethanol metabolism in the liver. Alcohol-induced acidosis is a mixed acid-base disturbance. Metabolic acidosis is due to lactic acidosis, ketoacidosis and acetic acidosis but the degree of each varies from patient to patient. Metabolic alkalosis is frequently present due to ethanol-induced vomiting. However, it could be overlooked because of an indirect loss of sodium bicarbonate (as sodium B-hydroxybutyrate in the urine). Nevertheless, the accompanying reduction in ECF volume may play an important role in the pathogenesis of alcoholic acidosis because it could lead to a relative insulin deficiency. Treatment of alcohol acidosis should include sodium, chloride, potassium, phosphorus, magnesium and thiamine replacements along with attention to concomitant clinical problems. Unless hypoglycemia is present, glucose need not be given immediately. We feel that insulin should be withheld unless life-threatening acidemia is present or expected. Lastly, alcohol need not be detected on admission to make the diagnosis of this metabolic disturbance. However, when present, it could contribute directly to the lactic, acetic and B-hydroxybutyric acidoses. With respect to the theoretical constraints on ethanol metabolism, it appears that "overproduction" of NADH in the liver is best averted by converting ethanol to B-hydroxybutyric acid.

Prevention possibility for brain dysfunction in rat with the fetal alcohol syndrome--low-zinc-status and hypoglycemia

As a treatable cause of CNS dysfunctions in the fetal alcohol syndrome (FAS), low-zinc-status in addition to hypoglycemia has been investigated in experimental rat models. During the premating period female rats of an ethanol group and a control group received 30% ethanol (E) and water (W), respectively. During pregnancy, some of both groups received zinc or nicotinamide-adenine dinucleotide (NAD) or nicotinamide throughout pregnancy and glucose for gestational day (gd) 15 to 19 with E or W. Independent of maternal blood glucose levels, maternal insulin levels were lower on gd 15 and 18 in the ethanol group than in the control one. A decrease in the activity of carbonic anhydrase in the hippocampal area on postnatal day (pd) 1 was observed in the ethanol group. Administration of zinc with E resulted in a better effect on fetal total body weight and on preventing resorption, mean fetal body weight and protein content in the cerebrum than administration of E alone. Administration of glucose only in the late gestational period resulted in a better effect on fetal cerebral weight than administration of E alone, with a decrease in the litter size. Administration of zinc with E during pregnancy resulted in higher maternal serum zinc levels, without an increase in fetal cerebral zinc content, than administration without zinc with E. There was a positive correlation between fetal body ethanol levels and maternal blood ethanol levels, and a negative correlation between fetal body ethanol levels and fetal total body weight. The beneficial effect of supplementary zinc on fetal growth may possibly help preventing the CNS dysfunctions of FAS, but it is important that the effect was not good compared to the control without E.