Higher Liver Fat Content Research Articles

The AGEs-RAGE axis and nonalcoholic steatohepatitis: the evidence mounts

I read with great interest the recent article by Kimura et al. [1] about the effects of atorvastatin treatment on advanced glycation end products (AGEs) in patients with nonalcoholic steatohepatitis (NASH). The authors elegantly demonstrated that atorvastatin given at 10 mg daily for 12 months successfully reduced glyceraldehyde-derived AGEs while improving the steatosis grade and nonalcoholic fatty liver disease (NAFLD) activity score. These results suggest a crucial role for AGEs in the pathogenesis of NASH and open an avenue for AGEs-targeted treatment of one of the top three leading causes of cirrhosis. One of the major shortcomings of the study by Kimura, however, was the failure to clarify and discuss the potential role played by the receptor for advanced glycation end products (RAGE) in their findings. Previous studies have shown that interactions between AGEs and RAGE can promote a number of adverse physiologic pathways, such as oxidative stress, inflammation, and insulin resistance [2–4], all of which have been implicated in the development of NASH. Conversely, circulating soluble isoforms of RAGE (sRAGE) can inhibit RAGE-induced activation of these pathways [5, 6], and therefore, sRAGE could conceivably protect against the development of NAFLD and NASH. In fact, we have previously examined the relationship between circulating levels of sRAGE and NAFLD in humans and demonstrated that levels of sRAGE are highly reduced in the setting of NASH and inversely correlated with ALT and AST [7]. Previous studies have also clearly shown that atorvastatin can influence the expression of sRAGE and cell-bound RAGE both in vitro and in vivo [8–11]. Beside RAGE, AGEs bind to other receptors, including macrophage scavenger receptors I and II, including CD36 [12]. Interestingly, Greco et al. [13] have demonstrated that CD36 is one of the most important genes found to be upregulated in subjects with high liver fat content. Taken together, the AGEs-RAGE axis is emerging as a core piece in the pathophysiology of insulin resistance, NAFLD and NASH, and evidence suggests that atorvastatin may influence not only AGEs, but also sRAGE. Kimura et al. are to be congratulated for their important piece of work expanding the current knowledge on the role of AGEs in NASH. Regrettably, however, the paper offers only a partial insight on this issue as the potential mediating role of sRAGE on the authors’ findings was not addressed. Future studies in the field should not ignore this important point.

Inverse association between liver fat content and hepatic glucose uptake in patients with type 2 diabetes mellitus

The objective of this research was to study (1) the mutual relationship between liver fat content (LFC) and hepatic glucose uptake (HGU) in patients with type 2 diabetes mellitus and (2) the relationship between changes in LFC and HGU uptake induced by rosiglitazone in these patients. Liver fat was measured with proton magnetic resonance spectroscopy and insulin-stimulated HGU with [ 18F]-labeled 2-fluoro-2-deoxyglucose positron emission tomography in 54 patients with type 2 diabetes mellitus and 8 healthy subjects. Measurements were repeated in diabetic patients after a 16-week intervention period with rosiglitazone (n = 27) or placebo (n = 27). Patients with diabetes had lower HGU (24.5 ± 14.2 vs 35.6 ± 9.7 μmol/[kg min], P < .01) and higher LFC (10.9% ± 9.2% vs 2.5% ± 1.4%, P < .001) compared with healthy subjects. Liver fat was inversely associated with HGU ( r = −0.31, P < .05), but more strongly with whole-body insulin sensitivity and adiponectin levels. Rosiglitazone treatment reduced liver fat by 24.8% ( P = .01 vs placebo) and increased HGU by 29.2% ( P = .013 vs placebo). This decrease in LFC was best explained by the increment in suppression of nonesterified fatty acid levels during hyperinsulinemia ( P < .001) and improved glycemic control ( P = .034), but not by changes in HGU. A significant inverse relationship between LFC and HGU was observed, but changes were not related. This suggests that the beneficial effects of rosiglitazone on liver metabolism are indirect and can be partly explained by increased suppression of nonesterified fatty acid levels, leading to reduced liver fat.

Gene expression in human NAFLD

Despite the high prevalence of nonalcoholic fatty liver disease (NAFLD), little is known of its pathogenesis based on study of human liver samples. By the use of Affymetrix GeneChips (17,601 genes), we investigated gene expression in the human liver of subjects with extreme steatosis due to NAFLD without histological signs of inflammation (liver fat 66.0 +/- 6.8%) and in subjects with low liver fat content (6.4 +/- 2.7%). The data were analyzed by using sequence-based reannotation of Affymetrix probes and a robust model-based normalization method. We identified genes involved in hepatic glucose and lipid metabolism, insulin signaling, inflammation, coagulation, and cell adhesion to be significantly associated with liver fat content. In addition, genes involved in ceramide signaling (MAP2K4) and metabolism (UGCG) were found to be positively associated with liver fat content. Genes involved in lipid metabolism (PLIN, ACADM), fatty acid transport (FABP4, CD36), amino acid catabolism (BCAT1), and inflammation (CCL2) were validated by real-time PCR and were found to be upregulated in subjects with high liver fat content. The data show that multiple changes in gene expression characterize simple steatosis.

Effect of liver fat on insulin clearance

A fatty liver is associated with fasting hyperinsulinemia, which could reflect either impaired insulin clearance or hepatic insulin action. We determined the effect of liver fat on insulin clearance and hepatic insulin sensitivity in 80 nondiabetic subjects [age 43 +/- 1 yr, body mass index (BMI) 26.3 +/- 0.5 kg/m(2)]. Insulin clearance and hepatic insulin resistance were measured by the euglycemic hyperinsulinemic (insulin infusion rate 0.3 mU.kg(-1).min(-1) for 240 min) clamp technique combined with the infusion of [3-(3)H]glucose and liver fat by proton magnetic resonance spectroscopy. During hyperinsulinemia, both serum insulin concentrations and increments above basal remained approximately 40% higher (P < 0.0001) in the high (15.0 +/- 1.5%) compared with the low (1.8 +/- 0.2%) liver fat group, independent of age, sex, and BMI. Insulin clearance (ml.kg fat free mass(-1).min(-1)) was inversely related to liver fat content (r = -0.52, P < 0.0001), independent of age, sex, and BMI (r = -0.37, P = 0.001). The variation in insulin clearance due to that in liver fat (range 0-41%) explained on the average 27% of the variation in fasting serum (fS)-insulin concentrations. The contribution of impaired insulin clearance to fS-insulin concentrations increased as a function of liver fat. This implies that indirect indexes of insulin sensitivity, such as homeostatic model assessment, overestimate insulin resistance in subjects with high liver fat content. Liver fat content correlated significantly with fS-insulin concentrations adjusted for insulin clearance (r = 0.43, P < 0.0001) and with directly measured hepatic insulin sensitivity (r = -0.40, P = 0.0002). We conclude that increased liver fat is associated with both impaired insulin clearance and hepatic insulin resistance. Hepatic insulin sensitivity associates with liver fat content, independent of insulin clearance.

Adipose Tissue Inflammation and Increased Ceramide Content Characterize Subjects With High Liver Fat Content Independent of Obesity

We sought to determine whether adipose tissue is inflamed in individuals with increased liver fat (LFAT) independently of obesity. A total of 20 nondiabetic, healthy, obese women were divided into normal and high LFAT groups based on their median LFAT level (2.3 +/- 0.3 vs. 14.4 +/- 2.9%). Surgical subcutaneous adipose tissue biopsies were studied using quantitative PCR, immunohistochemistry, and a lipidomics approach to search for putative mediators of insulin resistance and inflammation. The groups were matched for age and BMI. The high LFAT group had increased insulin (P = 0.0025) and lower HDL cholesterol (P = 0.02) concentrations. Expression levels of the macrophage marker CD68, the chemokines monocyte chemoattractant protein-1 and macrophage inflammatory protein-1alpha, and plasminogen activator inhibitor-1 were significantly increased, and those of peroxisome proliferator-activated receptor-gamma and adiponectin decreased in the high LFAT group. CD68 expression correlated with the number of macrophages and crown-like structures (multiple macrophages fused around dead adipocytes). Concentrations of 154 lipid species in adipose tissue revealed several differences between the groups, with the most striking being increased concentrations of triacylglycerols, particularly long chain, and ceramides, specifically Cer(d18:1/24:1) (P = 0.01), in the high LFAT group. Expression of sphingomyelinases SMPD1 and SMPD3 were also significantly increased in the high compared with normal LFAT group. Adipose tissue is infiltrated with macrophages, and its content of long-chain triacylglycerols and ceramides is increased in subjects with increased LFAT compared with equally obese subjects with normal LFAT content. Ceramides or their metabolites could contribute to adverse effects of long-chain fatty acids on insulin resistance and inflammation.

Postprandial Lipemia Associates with Liver Fat Content

Postprandial lipemia and low adiponectin represent novel risk factors for vascular disease. This study aimed to determine whether liver fat content and adiponectin are predictors of postprandial triglyceride (TG)-rich lipoproteins (TRL). Twenty-nine men were allocated into subgroups with either low (< or =5%) or high (>5%) liver fat measured with magnetic resonance proton spectroscopy. Subjects underwent an oral fat tolerance test with measurements of postprandial TG, cholesterol, apolipoprotein B-48 (apoB-48), and apoB-100 in TRL fractions, a euglycemic hyperinsulinemic clamp, and determination of abdominal fat volumes by magnetic resonance imaging. Subjects with high liver fat displayed increased response of postprandial lipids in plasma, chylomicron, and very-low-density lipoprotein 1 (VLDL1) (Svedberg flotation rate 60-400) fractions. Liver fat correlated positively with postprandial responses (area under the curve) of TG (r = 0.597; P = 0.001), cholesterol (r = 0.546; P = 0.002), apoB-48 (r = 0.556; P = 0.002), and apoB-100 (r = 0.42; P = 0.023) in the VLDL1 fraction. Respective incremental areas under the curve correlated significantly with liver fat. Fasting adiponectin levels were inversely correlated with both postprandial lipids and liver fat content. Liver fat remained the only independent correlate in a multiple linear regression analysis for chylomicron and VLDL1 responses. Liver fat content is a close correlate of postprandial lipids predicting the responses of TRL in chylomicrons and VLDL1 better than measures of glucose metabolism or body adiposity. Low adiponectin concentration is closely linked to high liver fat content and impaired TRL metabolism. High liver fat content associated with postprandial lipemia represents potential risk factors for cardiovascular disease.

“Buffalo” hump in nonalcoholic fatty liver disease

I read with interest the recent article by Cheung et al.1 regarding the impact of fat distribution, as estimated by several anthropometric parameters, on the severity of nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome in obese NAFLD patients. Notably, they found that dorsocervical lipohypertrophy (“buffalo” hump) was the single greatest predictor of the histological severity of NAFLD, whereas waist circumference was the greatest predictor of the severity of metabolic syndrome.1 Dorsocervical lipohypertrophy (DCL) was diagnosed only clinically but no quantitative measure (for example, ultrasound imaging) was used for diagnosing the “hump” at the base of the neck. Obviously, this is a major limitation of the study. Additionally, it is conceivable that the differential impact of DCL and waist circumference on the severity of NAFLD histology and metabolic syndrome is simply due to the fact that they are only indirect and crude indices of abdominal visceral fat distribution.2 A direct and more accurate measure of abdominal visceral fat, obtained by computed tomography or magnetic resonance imaging,2 would be useful to explore this issue adequately. However, the authors have interestingly shown that DCL, which is commonly seen in Cushing's syndrome, is a highly prevalent condition (28.5%) in obese NAFLD patients,1 thus suggesting an underlying subclinical hypercortisolism in NAFLD. Regarding this, recent studies have consistently shown a subclinical hypothalamo-pituitary-adrenal (HPA) axis dysfunction in NAFLD. Westerbacka et al.3 reported that obese men with higher liver fat content (as evaluated by magnetic resonance imaging spectroscopy) have a selective increase in 24-hour urinary excretion of 5-beta-reduced cortisol metabolites and a lower ratio of urinary cortisol/cortisone metabolites than men with lower liver fat content. Saruc et al.4 found that postmenopausal women with NAFLD, as assessed by ultrasound, have higher plasma dehydroepiandrosterone levels than controls. Others have shown that obese individuals5 and overweight type 2 diabetic patients6 with ultrasonographically diagnosed NAFLD have higher 24-hour urinary free cortisol excretion and postdexamethasone suppression cortisol concentrations than nonsteatotic controls. More importantly, we have recently demonstrated that overweight patients with biopsy-proven NAFLD have a subclinical, chronic HPA axis activation (as reflected by the increased, albeit still normal, 24-hour urinary free cortisol values and the blunted suppression of cortisol levels by 1.0 mg-dexamethasone with normal serum corticosteroid-binding globulin concentrations) that is correlated to the histopathological severity of NAFLD (that is, necro-inflammatory grade and fibrosis stage) independently of multiple potential confounders, including insulin resistance and metabolic syndrome components.7 Overall, therefore, the evidence from these studies,3-7 although only correlative in nature, suggests the hypothesis that overweight/obese NAFLD patients have a subtle HPA axis dysfunction that is strongly correlated with the severity of NAFLD histology, leading to subclinical cortisol overproduction that might be implicated in the development/progression of NAFLD. Future prospective and interventional (by using a cortisol inhibitor or specific 11beta-hydroxysteroid dehydrogenase-type 1 inhibitors) studies are obviously needed to validate this hypothesis and to better understand the underlying biological mechanisms linking HPA axis dysfunction to the development of NAFLD. Giovanni Targher M.D.*, * Section of Endocrinology, Department of Biomedical and Surgical Sciences, University Hospital, Verona, Italy.

Liver steatosis coexists with myocardial insulin resistance and coronary dysfunction in patients with type 2 diabetes

Nonalcoholic fatty liver (NAFL) is a common comorbidity in patients with type 2 diabetes and links to the risk of coronary syndromes. The aim was to determine the manifestations of metabolic syndrome in different organs in patients with liver steatosis. We studied 55 type 2 diabetic patients with coronary artery disease using positron emission tomography. Myocardial perfusion was measured with [15O]H2O and myocardial and skeletal muscle glucose uptake with 2-deoxy-2-[18F]fluoro-D-glucose during hyperinsulinemic euglycemia. Liver fat content was determined by magnetic resonance proton spectroscopy. Patients were divided on the basis of their median (8%) into two groups with low (4.6 +/- 2.0%) and high (17.4 +/- 8.0%) liver fat content. The groups were well matched for age, BMI, and fasting plasma glucose. In addition to insulin resistance at the whole body level (P = 0.012) and muscle (P = 0.002), the high liver fat group had lower insulin-stimulated myocardial glucose uptake (P = 0.040) and glucose extraction rate (P = 0.0006) compared with the low liver fat group. In multiple regression analysis, liver fat content was the most significant explanatory variable for myocardial insulin resistance. In addition, the high liver fat group had increased concentrations of high sensitivity C-reactive protein, soluble forms of E-selectin, vascular adhesion protein-1, and intercellular adhesion molecule-1 (P < 0.05) and lower coronary flow reserve (P = 0.02) compared with the low liver fat group. In conclusion, in patients with type 2 diabetes and coronary artery disease, liver fat content is a novel independent indicator of myocardial insulin resistance and reduced coronary functional capacity. Further studies will reveal the effect of hepatic fat reduction on myocardial metabolism and coronary function.

Cardiovascular disease in HIV-positive patients

Cardiovascular disease in HIV-positive patients

Liver Fat and Insulin Resistance Are Independently Associated with the −514C&gt;T Polymorphism of the Hepatic Lipase Gene

Liver fat predicts insulin resistance in humans. So far, there is not much information on genetic determinants of liver fat. Hepatic lipase is a liver-specific enzyme that regulates lipid metabolism. First, our object was to investigate whether the functional -514C>T polymorphism of the hepatic lipase gene is associated with liver fat content and with insulin sensitivity. Second, because this polymorphism displays gene-nutrient interactions, we assessed gene-gene interactions with the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma(2) on liver fat content and insulin sensitivity. Cross-sectional data from a total of 1070 nondiabetic subjects were analyzed. Insulin sensitivity was estimated from a 75-g oral glucose tolerance test. A subgroup of 115 subjects underwent measurements of liver fat. The -514C>T polymorphism of the hepatic lipase gene was associated with higher liver fat content (P = 0.005) and lower insulin sensitivity (P = 0.02), both after adjustment for age, gender, and percentage of body fat. This was independent of serum adiponectin concentrations (P = 0.01 and 0.03). However, there was an interaction of the -514C>T polymorphism with the Pro12Ala variant on liver fat (P = 0.09) and insulin sensitivity (P = 0.01). Subjects carrying the -514C>T polymorphism had higher liver fat content and were insulin resistant only before the background of the Pro/Pro genotype of the Pro12Ala polymorphism. The -514C>T polymorphism of the hepatic lipase gene is associated with higher liver fat content and lower whole-body insulin sensitivity. However, these effects are modulated by the common Pro12Ala polymorphism in peroxisome proliferator-activated receptor-gamma(2). These findings may be relevant for intervention strategies to prevent increase in liver fat content and insulin resistance.

Effects of identical weight loss on body composition and features of insulin resistance in obese women with high and low liver fat content.

Our objective was to determine how 8% weight loss influences subcutaneous, intra-abdominal, and liver fat (LFAT), as well as features of insulin resistance, in obese women with high versus low LFAT. A total of 23 women with previous gestational diabetes were divided into groups of high (9.4 +/- 1.4%) and low (3.3 +/- 0.4%) LFAT based on their median LFAT (5%) measured with proton spectroscopy. Both groups were similar with respect to age, BMI, and intra-abdominal and subcutaneous fat. Before weight loss, women with high LFAT had higher fasting serum insulin and triglyceride concentrations than women with low LFAT. At baseline, LFAT correlated with the percent of fat (r = 0.44, P < 0.05) and saturated fat (r = 0.45, P < 0.05) of total caloric intake but not intra-abdominal or subcutaneous fat or fasting serum free fatty acids. Weight loss was similar between the groups (high LFAT -7.4 +/- 0.2 vs. low LFAT -7.7 +/- 0.3 kg). LFAT decreased from 9.4 +/- 1.4 to 4.8 +/- 0.7% (P < 0.001) in women with high LFAT and from 3.3 +/- 0.4 to 2.0 +/- 0.2% (P < 0.001) in women with low LFAT. The absolute decrease in LFAT was significantly higher in women with high than low LFAT (-4.6 +/- 1.0 vs. -1.3 +/- 0.3%, P < 0.005). The decrease in LFAT was closely correlated with baseline LFAT (r = -0.85, P < 0.001) but not with changes in the volumes of intra-abdominal or subcutaneous fat depots, which decreased similarly in both groups. LFAT appears to be related to the amount of fat in the diet rather than the size of endogenous fat depots in obese women. Women with initially high LFAT lost more LFAT by similar weight loss than those with low LFAT, although both groups lost similar amounts of subcutaneous and intra-abdominal fat. These data suggest that LFAT is regulated by factors other than intra-abdominal and subcutaneous fat. Therefore, LFAT does not appear to simply reflect the size of endogenous fat stores.

Fat accumulation in the liver is associated with defects in insulin suppression of glucose production and serum free fatty acids independent of obesity in normal men.

We determined whether interindividual variation in hepatic insulin sensitivity could be attributed to variation in liver fat content (LFAT) independent of obesity. We recruited 30 healthy nondiabetic men whose LFAT (determined by proton spectroscopy); intraabdominal, sc, and total (determined by magnetic resonance imaging) fat; and insulin sensitivity of endogenous glucose rate of production (R(a)) and suppression of serum FFA [euglycemic insulin clamp combined with [3-(3)H]glucose (0-300 min); insulin infusion rate, 0.3 mU/kg.min, 120-300 min] were measured. The men were divided into groups of low (mean +/- SD, 1.7 +/- 0.2%) and high (10.5 +/- 2.0%) LFAT based on their median fat content. The low and high LFAT groups were comparable with respect to age (44 +/- 2 vs. 42 +/- 2 yr), body mass index (25 +/- 1 vs. 26 +/- 1 kg/m(2) ), waist to hip ratio (0.953 +/- 0.013 vs. 0.953 +/- 0.013), maximal oxygen uptake (35.6 +/- 1.5 vs. 33.5 +/- 1.5 ml/kg.min), and intraabdominal, sc, and total fat. The high compared with the low LFAT group had several features of insulin resistance, including fasting hyperinsulinemia (7.3 +/- 0.6 vs. 5.3 +/- 0.6 mU/liter; P < 0.02, high vs. low LFAT) hypertriglyceridemia (1.4 +/- 0.2 vs. 0.9 +/- 0.1 mmol/liter; P < 0.02), a low high density lipoprotein (HDL) cholesterol concentration (1.4 +/- 0.1 vs. 1.6 +/- 0.1 mmol/liter; P < 0.05), and a higher ambulatory 24-h systolic blood pressure (130 +/- 3 vs. 122 +/- 3 mm Hg; P < 0.05). Basal glucose R(a) and serum FFA were comparable between the groups, whereas insulin suppression of glucose R(a) [51 +/- 8 vs. 20 +/- 12 mg/m(2).min during 240-300 min (P < 0.05) or -55 +/- 7 vs. -85 +/- 12% below basal (P < 0.05, high vs. low LFAT)] and of serum FFA (299 +/- 33 vs. 212 +/- 13 micromol/liter; 240-300 min; P < 0.02) were impaired in the high compared with the low LFAT group. Insulin stimulation of glucose Rd were comparable in the men with high LFAT (141 +/- 12 mg/m(2).min) and those with low LFAT (156 +/- 14 mg/m(2).min; P = NS). Fat accumulation in the liver is, independent of body mass index and intraabdominal and overall obesity, characterized by several features of insulin resistance in normal weight and moderately overweight subjects.

Interrelationship Between the Effects of Dietary Factors and Feed Withdrawal on the Content and Composition of Liver Fat in Broiler Chicks

Four experiments were carried out to evaluate the effects of the composition and pelleting of diets fed to broiler chicks up to marketing age on changes in their liver size and the content and composition of liver fat due to feed withdrawal (FW) during 0, 10, and 24 h.Birds not exposed to FW that were fed diets with high energy to protein ratio (E:P) and diets in pelleted form—diets that increase fattening—had significantly (P < 0.05) higher liver fat content than those fed diets with the recommended E:P and in mash form, respectively. Those fed pellets also had higher liver weight. Dietary energy level did not affect these variables. Feed withdrawal for 10 or 24 h decreased, at times significantly, liver weight and its fat content, irrespective of the diets fed previously. The values observed after FW were not affected by the dietary factors evaluated.The composition of liver fatty acid in chicks not exposed to FW was markedly affected by increases in dietary energy (soybean oil) level and E:P. The main effects of the former were increased levels of stearic, linoleic, and arachidonic acids and a decreased level of oleic acid; those of the latter were an increased level of oleic and decreased levels of stearic, linoleic, and arachidonic acids. Irrespective of the diets used, FW increased the concentrations of stearic, linoleic, and arachidonic acids, and decreased those of palmitic and oleic acids. This effect on arachidonic acid was consistently significant, whereas the effects on the other fatty acids were significant in two out of three experiments. Due to these effects of FW, part of the differences in the composition of liver fatty acids caused by dietary factors observed in fed chicks, completely disappeared after FW.The length of FW (10 vs 24 h) did not affect liver size or fat content, but the concentrations of oleic and arachidonic acids in liver fat were significantly higher in birds exposed to 24 h of FW.It was concluded that the composition and form of the diets markedly affect liver weight and the content and composition of its fat in birds not exposed to FW. The effects of the dietary factors on liver size and its fat content completely disappear after 24 h of FW.

Influence of Diet Composition on Hepatic Lipid Deposition in Two Lines of Australorps Selected for Liver Fat Differences

This investigation was conducted to determine if the level of liver fat in Black Australorp laying hens, which had been selected over several generations for high or low liver fat content, would respond to changes in diet composition similar to the response of commercial strains of White Leghorns. In the first experiment, the two selected lines were fed either a corn-soybean diet (CS) or an tsonitrogenous and isoenergetic diet containing 4.89% each of fish meal, alfalfa meal, and torula yeast (FAY) for 6 weeks. Liver lipid was significantly higher for the high (19.4%) than for the low line (10.8%), but the FAY diet did not significantly affect this parameter. In a second 6-week experiment, the high and low lines of Black Australorps and unselected commercial White Leghorn hens were fed either the CS diet or one containing 14.67% distillers dried grains with solubles (DDGS). The DDGS significantly reduced both liver lipid and relative liver weight in Leghorns but not in the low and high liver fat Black Australorp lines. These results indicate that the mechanism of hepatic lipid accumulation in the genetically selected birds is different from that caused by feeding Leghorn hens a simplified CS diet and that the high liver fat line would not be useful in delineating nutritional effects on hepatic lipid accumulation.

Effects of Different Cereal Grains in Diets for Laying Hens on Production Parameters and Liver Fat Content ,

Two experiments were conducted with White Leghorn laying hens to study the effects of different cereal grains on production criteria and liver fat content. The results of Experiment 1, in which pullets 21 weeks of age were used for a period of 22 weeks indicated that Gaines wheat or triticale (Trailblazer) were equal to corn in supporting egg production, egg weight and body weight, with comparable feed consumption. Henry wheat (a hard red winter class) was slightly, yet significantly (P < 0.05) inferior to corn for the above criteria. No significant differences were observed among four treatments in wet liver weight and liver fat content. Hens fed the corn diet had significantly (P < 0.05) lower carcass fat followed by the hens fed triticale in comparison with those fed Gaines or Henry wheat. Mortality was very low and not related to dietary treatments. Neither dietary fat nor energy content was related to fat content of liver and carcass of the hens. Body weight and liver fat content were not closely related to each other. Wet liver weight was the only significantly (P < 0.05) related factor to liver fat content.In the second experiment, in which hens 33 weeks of age were used for an experimental period of 20 weeks, opaque-2 corn was slightly superior to normal corn and triticale was comparable to normal corn in supporting egg production and egg weight. Supplementation of the diets containing the two corns and triticale with lysine failed to improve egg production or egg weight. Hens fed the diets containing either normal corn or opaque-2 corn as the only grain in the diet had significantly (P < 0.05) higher liver fat content in comparison with hens fed the diet containing triticale as the only grain. Mortality, however, was much higher among hens fed triticale-containing diets in comparison with groups fed corn-containing diets in spite of the fact that they had significantly lower liver fat content. Regardless of dietary treatments or grains used, the hens that died were diagnosed to have fatty liver hemorrhagic syndrome. Dietary fat content was positively and significantly (P < 0.05) related to liver fat content. Dietary energy or body weight was not closely related to liver fat content. Liver fat content and mortality were negatively related to each other. The higher fat content did not adversely affect laying performance.

Increased susceptibility to carbon tetrachloride poisoning in the rat after pretreatment with oral phenobarbitone

Pretreatment of rats with phenobarbitone, dissolved in the drinking water, increases their susceptibility to CCl 4 poisoning. The median lethal dose ( LD50) falls from 3.6 ml CCl 4/kg in control animals to 0.5 ml/kg in phenobarbitone pretreated animals. 0.25 ml/kg of CCl 4 administered orally produces severe liver damage in phenobarbitone pretreated animals as shown by high liver fat and water content, and high plasma isocitrate dehydrogenase and bilirubin levels. This dose of CCl 4 produces only slight damage in control animals. Control animals given 2.5 ml/kg CCl 4 have a similar degree of liver damage to that found in phenobarbitone treated animals given 0.25 ml/kg CCl 4. Both groups metabolise about 12 mg/kg of the administered CCl 4 to CO 2, in 6 hr. Phenobarbitone pretreatment increases metabolism of CCl 4 to CO 2 both in vivo and in vitro. Comparison of CCl 4 levels in the blood and liver of pretreated and control animals suggest that the toxic effects cannot be related to the action of unaltered CCl 4, and strengthen the view that CCl 4 must be metabolised to cause cell damage. The nature of the toxic metabolite remains uncertain.