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Objective Hypertrophic obesity is associated with impaired insulin sensitivity and lipid-mobilizing activity of zinc-α2-glycoprotein. Adipose tissue (AT) of growth hormone (GH) -deficient patients is characterized by extreme adipocyte hypertrophy due to defects in AT lipid metabolism. It was hypothesized that zinc-α2-glycoprotein is regulated by GH and mediates some of its beneficial effects in AT. Methods AT from patients with GH deficiency and individuals with obesity-related GH deficit was obtained before and after 5-year and 24-month GH supplementation therapy. GH action was tested in primary human adipocytes. Relationships of GH and zinc-α2-glycoprotein with adipocyte size and insulin sensitivity were evaluated in nondiabetic patients with noncancerous cachexia and hypertrophic obesity. Results AT in GH-deficient adults displayed a substantial reduction of zinc-α2-glycoprotein. GH therapy normalized AT zinc-α2-glycoprotein. Obesity-related relative GH deficit was associated with almost 80% reduction of zinc-α2-glycoprotein mRNA in AT. GH increased zinc-α2-glycoprotein mRNA in both AT of obese men and primary human adipocytes. Interdependence of GH and zinc-α2-glycoprotein in regulating AT morphology and metabolic phenotype was evident from their relationship with adipocyte size and AT-specific and whole-body insulin sensitivity. Conclusions The results demonstrate that GH is involved in regulation of AT zinc-α2-glycoprotein; however, the molecular mechanism linking GH and zinc-α2-glycoprotein in AT is yet unknown.

Objective To examine the regulatory aspects of zinc-α2-glycoprotein (ZAG) association with obesity-related insulin resistance. Methods ZAG mRNA and protein were analyzed in subcutaneous adipose tissue (AT) and circulation of lean, obese, prediabetic, and type 2 diabetic men; both subcutaneous and visceral AT were explored in lean and extremely obese. Clinical and ex vivo findings were corroborated by results of in vitro ZAG silencing experiment. Results Subcutaneous AT ZAG was reduced in obesity, with a trend to further decrease with prediabetes and type 2 diabetes. ZAG was 3.3-fold higher in subcutaneous than in visceral AT of lean individuals. All differences were lost in extreme obesity. Obesity-associated changes in AT were not paralleled by alterations of circulating ZAG. Subcutaneous AT ZAG correlated with adiposity, adipocyte hypertrophy, whole-body and AT insulin sensitivity, mitochondrial content, expression of GLUT4, PGC1α, and adiponectin. Subcutaneous AT ZAG and adipocyte size were the only predictors of insulin sensitivity, independent on age and BMI. Silencing ZAG resulted in reduced adiponectin, IRS1, GLUT4, and PGC1α gene expression in primary human adipocytes. Conclusions ZAG in subcutaneous, but not in visceral AT, was markedly reduced in obesity. Clinical, cellular, and molecular evidence indicate that ZAG plays an important role in modulating whole-body and AT insulin sensitivity.

This study was aimed to evaluate possible obesogenic and diabetogenic impact of highly increased serum level of persistent organochlorinated pollutants POPs, such as polychlorinated biphenyls (PCBs), dichlorodiethyl-dichloroethylene (p,p'-DDE), and hexachlorobenzene (HCB), on the level of obesity markers (cholesterol and triglyceride level in serum, and body mass index [BMI]) and diabetes markers (fasting glucose and fasting insulin in serum) in inhabitants of Eastern Slovakia.In young (21-40 years) males (n=248) and females (n=330) as well as in old (41-75 years) males (n=586) and females (n=889), the serum levels of 15 polychlorinated biphenyl congeners (Σ15PCBs), p,p'-DDE and HCB, and serum insulin, testosterone, total cholesterol, triglycerides and glucose levels have been estimated by high resolution gas chromatography/mass spectrometry and by the appropriate electrochemiluminiscent immunoassay or chemical methods, respectively.In both age groups of males and females, the levels of Σ15PCBs, p,p'-DDE, and HCB were very high and their mutual interrelations were highly significant (p0.01). However, it should be noted that no significant changes were found in individual variables related to very high level of Σ15PCBs, except of increased BMI (p0.05) in females.In all ages and gender groups, defined above general as related to increasing level of individual OCPs in individual age and gender groups, significant increase in cholesterol and triglyceride levels as well as BMI values, supported their obesogenic effect, while significant increase in fasting glucose and insulin in serum, supported their diabetogenic effect. Finally, highly significant decrease in testosterone level, as found in both young and old males, supported the antiandrogenic effect, namely of HCB. However, somewhat less of p,p'-DDE, while PCBs did not show any such effect in spite of their very high level.Highly increased blood levels of diabetes (fasting glucose and insulin) and obesity markers (cholesterol, triglyceride and BMI) were found in large groups of males and females in highly polluted area of Slovakia. Significant decrease in testosterone level was also observed in males.

Phosphorus magnetic resonance spectroscopy (31P-MRS) enables the non-invasive evaluation of muscle metabolism. Resting Pi-to-ATP flux can be assessed through magnetization transfer (MT) techniques, and maximal oxidative flux (Qmax) can be calculated by monitoring of phosphocreatine (PCr) recovery after exercise. In this study, the muscle metabolism parameters of 13 overweight-to-obese sedentary individuals were measured with both MT and dynamic PCr recovery measurements, and the interrelation between these measurements was investigated. In the dynamic experiments, knee extensions were performed at a workload of 30% of maximal voluntary capacity, and the consecutive PCr recovery was measured in a quadriceps muscle with a time resolution of 2 s with non-localized 31P-MRS at 3 T. Resting skeletal muscle metabolism was assessed through MT measurements of the same muscle group at 7 T. Significant linear correlations between the Qmax and the MT parameters kATP (r = 0.77, P = 0.002) and FATP (r = 0.62, P = 0.023) were found in the study population. This would imply that the MT technique can possibly be used as an alternative method to assess muscle metabolism when necessary (e.g. in individuals after stroke or in uncooperative patients). Copyright © 2013 John Wiley & Sons, Ltd.

Altered adipose tissue formation is a well-known effectors of obesity and T2D. Here, we describe the role of Lrh1 and its co-repressor Shp in the control of adipocyte formation. Expression of Lrh1 in the pre-adipocyte containing SVF is induced in obese mice models and humans while Shp expression is reduced. We demonstrate, that Lrh1 is an inhibitor of adipogenesis while Shp acts functions as an activator through repression of Lrh1 activity. This regulation is at least in part modulated by estradiol conversion through the regulation of Cyp19a1 gene expression. In vivo, loss of Lrh1 leads to induced adipogenesis, while loss of Shp causes uncontrolled activation of Lrh1 and reduced adipogenesis. As Shp expression has been linked to the development of obesity and metabolic disorders, it is possible that alterations of the Shp/Lrh1 network lead to changes in adipocyte formation, which might contribute to the development of obesity associated T2D., Molecular Metabolism, 2 (3)

A heavily polluted area of Eastern Slovakia was targeted by the PCBRISK cross-sectional survey to search for possible links between environmental pollution and both prediabetes and diabetes.Associations of serum levels of five persistent organic pollutants (POPs), namely polychlorinated biphenyls (PCBs), 2,2'-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE), 2,2'-bis(4-chlorophenyl)-1,1,1-trichloro-ethane (p,p'-DDT), hexachlorobenzene (HCB) and beta-hexachlorocyclohexane (beta-HCH), with prediabetes and diabetes were investigated in 2,047 adults. Diabetes and prediabetes were diagnosed by fasting plasma glucose in all participants and by OGTT in 1,220 compliant participants.Our population was stratified in terms of individual POPs quintiles and associations between environmental pollution, prediabetes and diabetes were investigated. Prevalence of prediabetes and diabetes increased in a dose-dependent manner, with individuals in upper quintiles of individual POPs showing striking increases in prevalence of prediabetes as shown by OR and 95% CI for PCBs (2.74; 1.92-3.90), DDE (1.86; 1.17-2.95), DDT (2.48; 1.77-3.48), HCB (1.86; 1.7-2.95) and beta-HCH (1.97; 1.28-3.04). Interestingly, unlike PCBs, DDT and DDE, increased levels of HCB and beta-HCH seemed not to be associated with increased prevalence of diabetes. Nevertheless, individuals in the 5th quintile of the variable expressing the cumulative effect of all five POPs (sum of orders) had a more than tripled prevalence of prediabetes and more than six times higher prevalence of diabetes when compared with the 1st referent quintile.Increasing serum concentrations of individual POPs considerably increased prevalence of prediabetes and diabetes in a dose-dependent manner. Interaction of industrial and agricultural pollutants in increasing prevalence of prediabetes or diabetes is likely.

OBJECTIVE It was aimed to evaluate some fundamental correlations of 15 individual PCB congeners and their sum with serum testosterone level in highly and long-term exposed males with special respect to minimize the interfering effect of age. METHODS A total of 834 males from eastern Slovakia (age range of 21-78 years; median, 75th and 90th percentile of 48, 54 and 58 years, respectively) were examined consisting of 432 males from highly polluted area and 402 males from the area of background pollution. In all of them the serum level of 15 polychlorinated biphenyl congeners (PCBs), hexachlorobenzene (HCB) and dichlorodiethyl-dichloroethylene (DDE) was measured by gas chomatography/mass spectrometry and total testosterone in serum was measured with the aid of electrochemiluminiscent immunoassay. Pearson's correlation coefficients for each individual PCB congener as well as for Sigma15PCBs with testosterone were assessed in the cohort of all 834 males and also in the cohort of 444 males with age range of 41-55 years in which any significant negative influence of age on testosterone level has not been found and thus the interfering effect of aging on that level was apparently minimized. RESULTS In the cohort of 834 males with high level of Sigma15PCBs (median = 885; range = 211-77,084; 5% - 95% = 377 - 4051 ng/g lipid) and highly significant negative correlation with age (r= 0.303; p

In polluted district of Michalovce in East Slovakia (POLL) and two districts with background pollution (BCGR) 2046 adults (834 males and 1212 females aged 20-75 years) were examined. Serum levels of thyrotropin (TSH), free thyroxine (FT4), total triiodothyronine (TT3) and antithyroperoxidase antibodies (TPOab) were estimated by electrochemiluminiscent assay and also these of 15 polychlorinated biphenyl congeners (PCBs), p,p'-DDE, p,p'-DDT, hexachlorobenzene (HCB) and hexachlorocyclohexane were measured by high resolution gas chromatography/mass spectrometry. In addition, also dioxins, furans, coplanar- and mono-ortho-PCBs as well as selected hydroxylated and methylsulphonated PCBs and DDE metabolites were measured by appropriate methods based on gas chromatography/mass spectrometry principle. In POLL significantly higher levels of all organochlorines were found than these in BCGR. When pooled values from both areas were stratified in terms of PCBs level and treated as continuous variables, positive association of PCBs with FT4 and TT3 was found, the latter two being also mutually associated. However, within the category of PCBs level

We examined 2,046 adults (834 males and 1,212 females aged 20-75 years) from polluted district in East Slovakia (POLL) and two neighboring upstream and upwind located districts of background pollution (BCGR). By ultrasound we estimated the thyroid volume (ThV), hypoechogenicity (HYE), nodules and cysts. Serum levels of thyrotropin (TSH), thyroperoxidase antibodies (TPOab) and thyroglobulin were estimated by electrochemiluminiscent assay and these of 15 PCB congeners, p,p'-DDE, p,p'-DDT, hexachlorobenzene (HCB) and hexachlorocyclohexane by high-resolution gas chromatography. In 320 subjects also selected hydroxylated and methylsulfonated PCB metabolites, polychlorinated dibenzo-dioxins (PCDDs), -furans (PCDFs), five dioxin-like coplanar and eight mono-ortho PCB congeners were estimated. Urinary iodine was measured by automatic microplate method. Reciprocal positive association was found between three major POPs (PCBs, DDE and HCB), the levels of these and also PCDDs plus PCDFs in polluted area being considerably higher than in background pollution area. ThV in groups of males and females from POLL with high PCBs level was significantly higher (p0.001 by t-test) then in age and sex matched groups from BCGR with low PCBs level. In 1,048 males and females aged60 years with serum PCBs level1,000 ng g(-1) lipid (median=1,756 ng g(-1)) a significant effect of age on ThV was found (p0.01 by ANOVA), while in 921 respective subjects with PCBs level1,000 ng g(-1) (median=661 ng g(-1)) it was not. These findings supported the view on the additional effect of PCBs on ThV other than that of age. Since the urinary iodine in both districts showed optimal range, any interfering effect of unsatisfactory iodine intake on ThV may be excluded. The frequency of autoimmune thyroiditis signs such as HYE, increased serum level of TPOab and TSH resulting in subclinical or overt thyroid hypofunction was positively associated with sex, age and organochlorine levels. The increase of such frequency in males with POPs levels was much more abrupt than that in females. No considerable differences in the frequency of thyroid nodules as related to PCBs level were found.

In a certain area of Michalovce district in East Slovakia, heavy industrial pollution by polychlorinated biphenyls (PCBs) developed in 1955-1984 and very high PCB levels in environmental and human samples are still persisting. Recently, a total of 2045 adults from this and the surrounding background pollution area have been examined using questionnaire data, thyroid volume by ultrasound (ThV), urinary iodine and serum levels of 15 PCB congeners, hexachlorobenzene (HCB), 2,2'-2-bis(4-chlorobiphenyl)-1,1-dichloroethylene (DDE), 2,2'-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), alpha-, beta- and gamma-hexachlorocyclohexane (HCH), thyrotropin (TSH), free thyroxine (FT4), anti-thyroperoxidase antibodies (TPOab) and fasting glucose. As based on our previous findings of strikingly high level of PCBs in fish from high pollution area (e.g. mean level of 375430 ng/g lipid) and considerably lower, but still relatively high level in background pollution area (e.g. mean PCB level of 5150 ng/g), the information on the frequency of fish meals and approximate annual consumption of fish from local waters was obtained by questionnaires. The association of contaminated fish consumption with very high blood levels of PCBs, DDE and HCB and increased ThV as well as with increased frequency of positive TPOab, high values of FT4 and impaired fasting glucose (IFG) was found. These associations were also confirmed in 16 marital pairs from high pollution area with very high PCB level in both members associated with high fish consumption. It was concluded that, due to persistent heavy pollution of waters, soil and food chain namely by PCBs, but also by pesticides (e.g. DDE and HCB) resulting from their previous extensive use in agriculture, the fish from local waters still remains the most important source of these toxic pollutants which results in considerable adverse health effects.

Familial hypercholesterolemia (FH) is the world's most abundant and the most common heritable disorder of lipid metabolism. The prevalence of the disease in general population is 1:500. Therefore the approximate number of FH patients all over the world is 14 million. From the genetic point of view the disease originates as a result of mutations in genes affecting the processing of LDL particles from circulation, resulting in an increase in LDL cholesterol and hence total cholesterol. These are mutations in genes encoding LDL receptor, apolipoprotein B, proprotein convertase subtilisin/kexin 9 and LDL receptor adaptor protein 1. Cholesterol depositing in tissues and blood vessels of individuals creates tendon xanthoma, xanthelesma and arcus lipoides cornae. Due to the increased deposition of cholesterol in blood vessels, atherosclerosis process is accelerated, what leads to a significantly higher risk of premature cardiovascular diseases. Therefore, early clinical diagnosis confirmed by the DNA analysis, and effective treatment are crucial to reduce the mortality and high risk of premature atherosclerotic complications.

Our previous studies have shown that insulin resistance (IR) in the hereditary hypertriglyceridemic (hHTg) rat is accompanied by a specific fatty acid (FA) profile in insulin target tissues, possibly due to a defect in the desaturation pathway. Increased dietary intake of n-3 polyunsaturated fatty acids (PUFAs) was shown to shape FA composition and to improve insulin sensitivity in this animal strain. Thus, the aim of this study is twofold: (1) to evaluate a defect in the FA desaturation by direct measurement of enzyme activity and gene expression for Delta-6 desaturase (Delta-6 D) in liver of hHTg rats and (2) to investigate the effect of dietary n-3 PUFAs on hepatic Delta-6 D in relation to tissue FA composition. Male Wistar or hHTg rats were fed ad libitum for 21 days either the basal or fish oil (FO)-supplemented diets. Triglyceride (Tg) levels in serum and tissue lipid extracts were measured with the aid of a commercially available enzymatic set. Hepatic activity of the Delta-6 D was determined radiometrically in a microsomal fraction using 1-(14)C-linoleic acid as a substrate. The Delta-6 D mRNA levels were measured using the Northern blot technique. Tissue FA composition was determined by gas chromatography in the total phospholipid fraction after TLC separation. Increased levels of Tg in hHTg rat circulation were accompanied by raised accumulation of Tg in skeletal muscles. FO feeding lowered the concentration of Tg in serum and prevented their accumulation in skeletal muscles of hHTg rats. A pronounced decrease in the hepatic Delta-6 D activity in hHTg rats (by about 80%) was not further diminished by FO feeding. On the other hand, the activity of Delta-6 D in liver of control rats was reduced by about 40% after FO supplementation. These changes were paralleled by a decrease in the Delta-6 D index as calculated from the liver phospholipid FA profile. In particular, an increase in the amount of 18:2 n-6 and a decrease in arachidonic acid and PUFA n-6 metabolites were found. The results indicate that a decrease of insulin action in hHTg rats is accompanied by an impairment of the hepatic Delta-6 D activity already at the gene level, which is not further affected by n-3 PUFA supplementation.

A summary of the Fourth International Smolenice Symposium on Lipids and Insulin Resistance focusing on “The Role of Fatty Acid Metabolism and Fuel Partitioning” is provided. Highlights and issues of the conference are mentioned, as well as strategies for the future.

We observed earlier that increased skeletal muscle lipid content in the hereditary hypertriglyceridemic (hHTg) rat is accompanied by a decline in plasma leptin. Leptin has recently been shown to enhance peripheral insulin sensitivity by decreasing the tissue triglyceride accumulation, possibly through regulation of fatty acid oxidation and lipogenesis. Thus, to test the hypothesis that insulin resistance and increased skeletal muscle lipid accumulation in hHTg rats are due to a defect in lipid catabolism, we measured mitochondrial and peroxisomal fatty acid oxidation and malonyl-CoA and acetyl-CoA carboxylase-2 content in skeletal muscles of these animals. In addition, we investigated possible molecular mechanisms responsible for the lower leptin levels in hHTg rats by measuring leptin and leptin-receptor (Ob-Ra) mRNA levels. We found the following: (1) in spite of a higher skeletal muscle malonyl-CoA content and an increased sensitivity of carnitine palmitoyltransferase-1 to malonyl-CoA, carnitine palmitoyltransferase-1 activity in muscle of hHTg rats was normal; (2) increased peroxisomal fatty acid oxidation did not seem to be sufficient to prevent the tissue lipid accumulation in these animals; (3) both lower leptin production by white adipose tissue and increased leptin uptake seem to be responsible for lower circulating leptin levels and therefore lower fatty acid catabolism.

An increased prevalence of thyroid antibodies was seen in employees of a factory that formerly produced polychlorinated biphenyls (PCBs). In this study, the authors expand the evaluation of possible long-term PCB effects by comparing the prevalence of glutamic acid decarboxylase (anti-GAD) antibodies with the development of diabetes mellitus. The sera of 240 factory employees and 704 control subjects were analyzed. Anti-GAD antibody values exceeded 1.20 U/ml in all employees (40.4%), was 4 times higher (p.001) than in all controls (10.5%), and were 5 times higher in employees aged 51-60 yr (53.2%) than in age-matched controls (10.5%) (p.001). Although the prevalence of diabetes could not be determined from this retrospective study, this is the first report of a possible relationship between xenobiotics and the prevalence of anti-GAD antibodies, and it supports the concept of an immunomodulatory effect of PCBs. However, such antibodies may be present decades before the development of clinical diabetes, and not all anti-GAD antibody-positive individuals become diabetic. Presently, it is unknown whether there is an increased prevalence of diabetes among the former factory employees.

Tetradecylthioacetic acid (TTA) is a non- � -oxi- dizable fatty acid analog, which potently regulates lipid ho- meostasis. Here we evaluate the ability of TTA to prevent diet-induced and genetically determined adiposity and insu- lin resistance. In Wistar rats fed a high fat diet, TTA admin- istration completely prevented diet-induced insulin resis- tance and adiposity. In genetically obese Zucker (fa/fa) rats TTA treatment reduced the epididymal adipose tissue mass and improved insulin sensitivity. All three rodent peroxi- some proliferator-activated receptor (PPAR) subtypes were activated by TTA in the ranking order PPAR � � PPAR � � PPAR � . Expression of PPARtarget genes in adipose tissue was unaffected by TTA treatment, whereas the hepatic ex- pression of PPAR � -responsive genes encoding enzymes in- volved in fatty acid uptake, transport, and oxidation was induced. This was accompanied by increased hepatic mitochondrial � -oxidation and a decreased fatty acid/ke- tone body ratio in plasma. These findings indicate that PPAR � -dependent mechanisms play a pivotal role, but ad- ditionally, the involvement of PPAR � -independent path- ways is conceivable. Taken together, our results suggest that a TTA-induced increase in hepatic fatty acid oxidation and ketogenesis drains fatty acids from blood and extrahe- patic tissues and that this contributes significantly to the beneficial effects of TTA on fat mass accumulation and pe- ripheral insulin sensitivity. —Madsen, L., M. Guerre-Millo, E. N. Flindt, K. Berge, K. J. Tronstad, E. Bergene, E. Sebok- ova, A. C. Rustan, J. Jensen, S. Mandrup, K. Kristiansen, I. Klimes, B. Staels, and R. K. Berge. Tetradecylthioacetic acid prevents high fat diet induced adiposity and insulin resis- tance. J. Lipid Res. 2002. 43: 742-750.

Background Inactivating mutations of the hypothalamic transcription factor singleminded1 (SIM1) have been shown as a cause of early-onset severe obesity. However, to date, the contribution of SIM1 mutations to the obesity phenotype has only been studied in a few populations. In this study, we screened the functional regions of SIM1 in severely obese children of Slovak and Moravian descent to determine if genetic variants within SIM1 may influence the development of obesity in these populations. Methods The SIM1 promoter region, exons and exon-intron boundaries were sequenced in 126 unrelated obese children and adolescents (2-18 years of age) and 41 adult lean controls of Slovak and Moravian origin. Inclusion criteria for the children and adolescents were a body mass index standard deviation score higher than 2 SD for an appropriate age and sex, and obesity onset at less than 5 years of age. The clinical phenotypes of the SIM1 variant carriers were compared with clinical phenotypes of 4 MC4R variant carriers and with 27 unrelated SIM1 and MC4R mutation negative obese controls that were matched for age and gender. Results Seven previously described SIM1 variants and one novel heterozygous variant p.D134N were identified. The novel variant was predicted to be pathogenic by 7 in silico software analyses and is located at a highly conserved position of the SIM1 protein. The p.D134N variant was found in an 18 year old female proband (BMI 44.2kg/m2; +7.5 SD), and in 3 obese family members. Regardless of early onset severe obesity, the proband and her brother (age 16 years) did not fulfill the criteria of metabolic syndrome. Moreover, the variant carriers had significantly lower preferences for high sugar (p = 0.02) and low fat, low carbohydrate, high protein (p = 0.02) foods compared to the obese controls. Conclusions We have identified a novel SIM1 variant, p.D134N, in 4 obese individuals from a single pedigree which is also associated with lower preference for certain foods.

Growth hormone (GH) supplementation therapy to adults with GH deficiency has beneficial effects on adipose tissue lipid metabolism, improving thus adipocyte functional morphology and insulin sensitivity. However, molecular nature of these effects remains unclear. We therefore tested the hypothesis that lipid-mobilizing adipokine zinc-α2-glycoprotein is causally linked to GH effects on adipose tissue lipid metabolism. Seventeen patients with severe GH deficiency examined before and after the 5-year GH replacement therapy were compared with age-, gender- and BMI-matched healthy controls. Euglycemic hyperinsulinemic clamp was used to assess whole-body and adipose tissue-specific insulin sensitivity. Glucose tolerance was determined by oGTT, visceral and subcutaneous abdominal adiposity by MRI, adipocyte size morphometrically after collagenase digestion, lipid accumulation and release was studied in differentiated human primary adipocytes in association with GH treatment and zinc-α2-glycoprotein gene silencing. Five-year GH replacement therapy improved glucose tolerance, adipose tissue insulin sensitivity and reduced adipocyte size without affecting adiposity and whole-body insulin sensitivity. Adipose tissue zinc-α2-glycoprotein expression was positively associated with whole-body and adipose tissue insulin sensitivity and negatively with adipocyte size. GH treatment to adipocytes in vitro increased zinc-α2-glycoprotein expression (>50%) and was paralleled by enhanced lipolysis and decreased triglyceride accumulation (>35%). Moreover, GH treatment improved antilipolytic action of insulin in cultured adipocytes. Most importantly, silencing zinc-α2-glycoprotein eliminated all of the GH effects on adipocyte lipid metabolism. Effects of 5-year GH supplementation therapy on adipose tissue lipid metabolism and insulin sensitivity are associated with zinc-α2-glycoprotein. Presence of this adipokine is required for the GH action on adipocyte lipid metabolism in vitro.

Fatty acid (FA) profiles of total serum lipids were determined by capillary gas chromatography in Type 2 diabetic patients (NIDDM) with diverse types of hyperlipidemia. In patients with hypertriglyceridemia (DM-HTG) and combined hypertriglyceridemia and hypercholesterolemia (DM-HLP), a significantly different total FA composition was found compared with healthy controls or diabetics with normal serum lipids. In particular, the proportions of saturated and monounsaturated FA were increased and the proportions of n-6 polyunsaturated FA were decreased. In DM-HLP patients, PUFA n-6 metabolites and C20-C22 PUFA were also decreased. Thus, hyperlipidemia shifts significantly the serum FA composition in NIDDM patients into an atherogenic profile. More study is needed, however, to understand if serum FA changes may contribute to the increased atherogenesis commonly found in these patients.

The effect of feeding Wistar rats with high-sucrose (63 wt% of sucrose, HS) or high-fat (30 wt% of fat, HF) diets for two weeks on serum selenium concentration and type I iodothyronine 5'-deiodinase (5'-DI) activity in liver was investigated. No significant differences in serum selenium concentration (as determined by graphite-furnace atomic absorption spectrometry) were found among the groups of rats fed basal, HS, or HF diets. A significant reduction of the 5'-DI activity (p < 0.005-0.05) was found in groups of rats fed either HS or HF diet in comparison with rats fed B diet. In conclusion, it is suggested that decreased 5'-DI activity in HS or HF diet-induced insulin resistance is not due to selenium status, but it may involve other dietary-related factors.

Structural changes in the ascending thoracic aorta of hereditary hypertriglyceridemic (hHTG), insulin-resistant, and hypertensive rats were studied using transmission electron microscopy. Normotensive Wistar rats were used as controls. The most-pronounced morphological changes were observed in the tunica intima. Endothelial cells of hHTG rats formed a continual layer around the whole circumference. Subendothelial space was enlarged. Some endothelial cells were delaminated from the subendothelial space by big lipid droplets that were often present in the subendothelial space, and the endothelial cells bulged out towards the lumen. Big electron-lucent lipid droplets were present in the majority of the endothelial cells and occupied the main part of the cytoplasm. Degenerative microvesicular and membranous material was present in the cytoplasm. Increased numbers of vesicles of Golgi apparatus and cisternae of endoplasmic reticulum were found. Similar morphological alterations, but in less-extended form, were observed in smooth muscle cells. The organization and orientation of smooth muscle cells were essentially intact. In muscle cells, lipid droplets were localized in close relation to Golgi complex and in dilated cisternae of the sarcoplasmic reticulum. Lipid droplets, degenerative material, myelin figures, myelinoid membranes, and vesicular components were also sporadically found in the intercellular space among muscle cells. This pilot morphological investigation provides further arguments for a thorough and more-focused electron microscopy study of conductance arteries of the hHTG rats.

This work was aimed to evaluate the fundamental relations between the blood levels of testosterone (TEST) and persistent organochlorinated pollutants (POPs) related to body mass index (BMI) and blood lipids in a cohort of heavily exposed males from Eastern Slovakia.In 429 middle aged (41-55 years) males heavily exposed to POPs the levels of 15 polychlorinated biphenyl congeners (Σ15PCBs), hexachlorobenzene (HCB), and dichlorodiethyl-dichloroethylene (p,p'-DDE) were measured by gas chromatography/mass spectrometry and the total testosterone (TEST) by electrochemiluminiscent immunoassay.After classifying the values of BMI, TEST, HCB, p,p'-DDE, and Σ15PCBs in quintiles and evaluating mutual interrelations of individual quintile counts in pairs of variables with chi-square, statistically significant interrelation was found for BMI/TEST (0.0001) and HCB/TEST (p0.001), but not for p,p'-DDE/TEST (p0.6036) and Σ15PCBs/TEST (p0.3246). Moreover, highly significant negative correlation was found between HCB and TEST by means of both Pearson (p0.01) and Spearman rank correlations (p0.0001). However, similar correlations performed between p,p'-DDE and Σ15PCBs did not reveal statistical significance. Finally, highly significant positive correlations were found between HCB and BMI, age, total lipids, and triglycerides. However, these correlations were less significant for p,p'-DDE and not significant or even negligibly negative for Σ15PCBs. In contrast, correlations of TEST with BMI and lipid fractions were significantly negative.It appears that HCB might play a role in a decrease of TEST in males with relatively narrow age range of males highly exposed to POPs. Highly significant positive correlation of HCB with BMI and blood lipids points out the role of BMI as an imaginary compartment closely related to the total body fat mass and representing a depot of POPs which is closely related to the level of POPs and lipids in blood. However, the differences in the affinity of individual POPs to BMI and blood lipids as well as the mechanism of their different relation to blood TEST levels remain to be still explained.

High sucrose feeding is known to induce the symptoms of so-called metabolic X syndrome (e.g., hypertriglyceridemia, hyperinsulinemia, insulin resistance, and hypertension) in rats. To elucidate whether the latter may also involve an alteration of the glucose transport in skeletal muscle, we determined GLUT4 gene expression and GLUT4 protein levels in muscle quadriceps femoris of Wistar rats fed ad libitum a basal or high (63 cal%) sucrose diet for 21 days. To test a possible beneficial effect of dietary omega-3 polyunsaturated fatty acids on the above parameters, additional groups of rats were fed the diets supplemented with marine fish oil (30 wt% omega-3 polyunsaturated fatty acids). A twofold increase in GLUT4 gene expression (dot blot analysis) was observed in the muscle of rats fed the high sucrose diet. Dietary fish oil reduced the GLUT4 gene expression in high sucrose-fed animals by about 50% of the values obtained in rats fed the basal diet plus fish oil. Western blot analysis of total muscle membrane fractions using specific antibodies against GLUT4 revealed no changes in the transporter levels in high sucrose-fed rats, and even a decrease in both, with fish oil-supplemented groups of animals. These data suggest that feeding high sucrose diet to rats is associated with an uncoupling between muscle GLUT4 mRNA and protein levels. On the other hand, it is notable that the decrease of GLUT4 protein found in rats fed the fish oil-supplemented diets was more pronounced in the group of animals fed the high sucrose diet.

High sucrose diet-induced insulin resistance and mild glucose intolerance are associated with decreased insulin binding to isolated adipocytes and reduced insulin action in adipose tissue. Enhanced dietary intake of omega-3 polyunsaturated fatty acids (n-3-FA) counteracts these disorders. To provide more information on the possible role of membrane-related glucose transport processes, basal and insulin-stimulated 2-deoxy-D-3H glucose uptake was evaluated in isolated adipocytes obtained from rats on various dietary regimens. For 2 weeks animals were fed three different isocaloric (18 cal% proteins, 19 cal% fat, and 63 cal% carbohydrate) diets: (1) a standard rat chow (B), (2) a high sucrose diet (S, 63 cal% sucrose), or (3) an S diet supplemented with marine fish oil (S + FO, Martens, 30 wt% of n-3-FA). High dietary n-3-FA intake resulted in a significant decline in both basal (0.05 +/- 0.01 pmol/10(6) fat cells; mean +/- SEM) and insulin-stimulated (10(-6) M) (0.20 +/- 0.01) glucose uptake when compared with the control (basal: 0.12 +/- 0.02; insulin: 0.35 +/- 0.02) and/or the S group (basal: 0.18 +/- 0.03; insulin: 0.43 +/- 0.03), indicating decreases in insulin responsiveness and sensitivity (ED50: B: 0.03 +/- 0.01; S: 0.03 +/- 0.01; S + FO: 0.73 +/- 0.2 nM; p < 0.01 for S + FO vs B and S + FO vs S). Fish oil supplementation induced an increase in adipocyte size (B: 69 +/- 1.6; S: 70 +/- 2.5 and S + FO: 76 +/- 2.2 microns; B: S + FO p < 0.05) and a decrease in plasma membrane microviscosity (B: 4.08 +/- 0.3; S: 5.39 +/- 0.5; S + FO: 3.10 +/- 0.3; p < 0.05). Rates of basal and insulin-stimulated glucose uptake did not correlate with plasma membrane microviscosity; however, a negative relation to fat cell size was found (r = -0.484; p < 0.05). On the other hand, a positive correlation between both basal (r = 0.504; p < 0.05) and insulin-stimulated (10(-6) M, r = 0.640; p < 0.02) glucose uptake and blood glucose levels was observed. In conclusion, these data (a) suggest a less important role of diet-induced changes in plasma membrane microviscosity for glucose uptake in adipose tissue, and (b) leave unclear the mechanism of why dietary fish oil decreases the sensitivity of glucose uptake to insulin in isolated rat adipocytes.

In hereditary HTG rats, basal systolic blood pressure using tail-cuff sphygmomanometry was significantly higher (122.1 +/- 2.1 mm Hg; n = 16) than that in NTG animals (107.1 +/- 1.52; n = 16). A low salt diet did not influence blood pressure in NTG rats during the consecutive 4 weekly periods. However, in the second week blood pressure in HTG rats rose significantly in both the control rats on a normal salt diet and those on a low salt diet (132.5 +/- 1.89, n = 8, and 132.6 +/- 1.93, n = 8). No further changes were registered in the third and fourth week in control HTG rats. On the other hand, blood pressure fell significantly in HTG rats on a low salt diet in the third week in comparison with the second week (119.5 +/- 3.2, n = 8), and it increased again in the fourth week (123.0 +/- 2.35, n = 8). Hormones in plasma were determined at the end of the experiment. Plasma levels of norepinephrine were not influenced by differences in salt intake and were significantly higher by about 45% in HTG than in NTG animals. The lowest concentration of corticosterone in plasma was found in control HTG rats (1.2 +/- 0.2 vs 4.6 +/- 0.8 micrograms/100 ml in control NTG rats). Nevertheless, corticosterone concentration increased in HTG rats on a low salt diet at comparable values found in NTG rats on a low salt diet (3.1 +/- 0.8 vs 4.3 +/- 1.5). Plasma renin activity and plasma aldosterone concentrations were not different in the NTG and HTG groups and were uninfluenced by the diets (Table 1). We conclude that the elevated blood pressure in HTG rats and its variations during the experiment may reflect more pronounced sympathetic activity in HTG rats rather than blood pressure dependency on different salt intake.

Our data indicate that (a) the existence of a defect in the clearance of circulating TG and persistence of muscle TG deposition in the high sucrose-fed neonatal streptozotocin diabetic rat, which (b) can only be partially corrected by raised dietary n-3 PUFA intake. (c) Skeletal muscle of STZ type II-like diabetic rats contains about 40% less glucose transporters, and (d) this situation cannot be changed by any of the dietary treatments employed. (e) These findings indicate that muscle TG accumulation may have no direct relation to glucose transport in muscle.

The role of different fat supplements (fish oil and cocoa butter), applied intragastrically for 3 weeks, on specific binding of T3 by rat liver nuclear receptors was examined. Fish oil (rich in n-3 polyunsaturated fatty acids) supplementation resulted in a significant (P < 0.05) enhancement of the maximal binding capacity (MBC) for T3 with a diminution of the apparent association constant (Ka). No changes in nuclear receptor MBC or Ka were observed after cocoa butter administration. Moreover, the rate of fatty acid synthesis in the liver was evaluated by measuring malic enzyme (EC. 1.1.1.40.) activity in rat liver cytosol, which was found to be decreased in both the cocoa butter- (P < 0.002) and the fish oil- (P < 0.001) treated rats. Interestingly, in fish oil-supplemented animals, not even a higher MBC value for the T3 receptors in liver nuclei and specific binding of T3 to its receptor were able to restore the activity of malic enzyme in liver cytosol. The findings of the same level of thyroid hormones—thyroxine (T4) and triiodothyronine (T3)—in blood of all groups showed that there was apparently no effect of fat supplementation on the thyroid function. However, it may be hypothesized that the decrease of malic enzyme activity in both fat-treated groups may have resulted from a decreased T4 to T3 conversion in liver cells. The data suggest the following: (a) increased dietary fat intake is accompanied by lower lipogenesis in the liver in relation to the degree of fat unsaturation; (b) although polyunsaturated dietary fat increases T3 receptor binding to liver nuclei; (c) thus, an uncoupling between T3 binding and action on malic enzyme activity during raised fish oil intake cannot be ruled out.

Background High dietary intake of saturated fat impairs insulin sensitivity and lipid metabolism. The influence of fatty acid chain length, however, is not yet fully understood, but evidence exists for different effects of saturated long-chain (LC) versus saturated medium-chain (MC) fatty acids (FA). Methods To investigate the effects of the FA chain length, male Wistar rats were fed high-fat diets containing triacylglycerols composed of either MC- or LCFA for 4 weeks; rats fed maintenance diet served as a control. The animals underwent euglycemic hyperinsulinemic clamping or oral metabolic tolerance testing respectively; enzyme activities of mitochondrial (EC2.3.1.21 carnitine palmitoyl transferase) and peroxisomal (EC1.3.3.6 acyl-CoA oxidase) FA oxidation were measured in liver and muscle. Results LCFA consumption resulted in higher fasted serum insulin and glucose concentrations compared to controls, while MCFA-fed animals did not differ from controls. Insulin sensitivity was reduced by 30% in the LCFA group while the MCFA group did not differ from controls. Feeding MCFA resulted in the controls' lowered fasted and post-prandial triacylglycerol concentration compared to LCFA, while triacylglycerol concentrations in muscle were higher in both high-fat groups compared to controls. No diet-induced changes were found in acyl-CoA oxidase (ACO) activity (liver and muscle), while LCFA feeding significantly raised carnitine palmitoyltransferase activity. Conclusions The chain length of saturated fatty acids in isocaloric diets affects insulin sensitivity, lipid metabolism and mitochondrial fatty acid oxidation without influencing body weight. While dietary LCFA clearly impair insulin sensitivity and lipid metabolism, MCFA seem to protect from lipotoxicity and subsequent insulin resistance without caloric restriction. Copyright © 2009 John Wiley & Sons, Ltd.

Heavy environmental pollution resulting from uncontrolled industrial and agricultural activities has occurred in several areas of Slovakia. So far, field surveys focused mainly on the thyroid have been conducted in one area polluted by nitrates and in a large area polluted mainly by organochlorinated toxicants. In children from the high nitrate area (HNA, n = 324) significantly higher thyroid volume (ThV) by ultrasound was found compared with age-matched children from surrounding areas with low nitrate (LNA, n = 764). In blood samples of 324 children from the HNA and of 100 children from the LNA no difference between areas was found in the level of total thyroxine (T4) and free triiodothyronine (T3). However, positive thyroid peroxidase antibodies (TPOAb) were found in 7/324 (2.2%) and thyrotropin (TSH) levels4.0 mIU/L in 13/324 (4.0%) of children from the HNA area, while no positive values were obtained in the LNA. In the area heavily polluted by an organochlorine (OC) cocktail consisting of polychlorinated biphenyls (PCBs), 2,2'-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE), hexachlorobenzene (HCB), and dioxins and furans (polluted area) and in the background pollution area (background area) a total of 2046 adults were examined. In polluted area very high blood levels of OCs were found as well as increased ThV and prevalence of thyroid hypoechogenicity by ultrasound. For the evaluation of data the level of PCBs was used as a marker of all OCs. Increasing PCB levels were significantly associated with the increase of free T4 (p0.001) and total T3 (p0.05) in blood, while slight but not significant negative association of PCBs was observed with the level of TSH. In both women and men the prevalence of TPOAb was significantly higher in polluted area. Although the absolute TPOAb prevalence in both areas was higher in women than that in men, the increase in polluted vs. background area was more striking in men. From these data it appears that the effects of environmental pollution on the thyroid cannot be neglected.

Central action of leptin on food intake and energy expenditure is integrated with leptin's peripheral action modulating the fatty acid and glucose metabolism and preventing the accumulation of lipids in nonadipose tissues. However, exact mechanism(s) of the leptin's action in the peripheral tissues has not yet been fully elucidated. Therefore, we investigated the effect of a single intravenous injection of leptin on palmitoyl-CoA and palmitoyl-carnitine oxidation rate in liver and skeletal muscle followed by measurements of the carnitine-palmitoyl transferase 1 (CPT1) activity and activities of ss-oxidation enzymes in mitochondria (acyl-CoA dehydrogenase) and in peroxisomes (acyl-CoA oxidase) of rats. Animals were euthanized and tissues and serum harvested 15 min, 1 hour, 3 hours and 6 hours after leptin administration. Intravenous leptin injection increased mitochondrial palmitoyl-CoA oxidation rate in both liver (95%; P

BACKGROUND: HDL-cholesterol (HDL-C) is a recognized athero-protective factor and low levels of HDL-C occur frequently in patients with coronary artery disease. Regulation of HDL-C level most probably results from the interaction of genes involved in lipoprotein metabolism and also from non-genetic factors. We studied associations and interactions among HindIII polymorphisms of the lipoprotein lipase gene LPL and selected non-genetic factors with respect to HDL-C levels in patients with coronary artery disease. PATIENTS AND METHODS: 288 Slovak patients (35% women) with documented coronary artery disease, age (mean ± SEM) 60 ± 1 years and BMI 29 ± 0.3 kg/m2, were examined and genotyped for LPL HindIII (rs320) using a PCR/RFLP method. HDL-C levels were determined in a direct enzymatic assay. RESULTS: In the sample overall there were no significant differences across the LPL genotypes in adjusted HDL-C levels or in other lipids, although a trend toward higher HDL-C and lower triglycerides in H-H- homozygotes was observed. Multiple linear regression identified a significant interaction between LPL HindIII and statin treatment, which together with sex and diabetes explained 12.1% of HDL-C variance. Accordingly, in statin-treated patients we observed significant stepwise increments of the HDL-C level related to the increasing number of H- alleles (P = 0.04 for linear trend), whereas no such association was observed in patients without hypolipidemic treatment. H-H- homozygotes had a 16% (0.19 mmol/l) higher level of HDL-C than the H+H+ homozygotes (P = 0.06). CONCLUSION: HDL-C may be influenced by an interaction between statin treatment and LPL HindIII genotype. However, the effect of this interaction appears to be small when compared with the effect of non-genetic factors. This finding requires replication in a pharmacogenetic study.

To study the mechanisms responsible for the hypotriglyceridemic effect of marine oils, we monitored the effects of high dietary intake of n-3 PUFA on hepatic and muscular beta-oxidation, plasma leptin concentration, leptin receptor gene expression, and in vivo insulin action. Two groups of male Wistar rats were fed either a high-fat diet [28% (w/w) of saturated fat] or a high-fat diet containing 10% n-3 PUFA and 18% saturated fat for 3 wk. The hypotriglyceridemic effect of n-3 PUFA was accompanied by increased hepatic oxidation of palmitoyl-CoA (125%, P < 0.005) and palmitoyl-L-carnitine (480%, P < 0.005). These findings were corroborated by raised carnitine palmitoyltransferase-2 activity (154%, P < 0.001) and mRNA levels (91%, P < 0.01) as well as by simultaneous elevation of hepatic peroxisomal acyl-CoA oxidase activity (144%, P < 0.01) and mRNA content (82%, P < 0.05). In contrast, hepatic carnitine palmitoyltransferase-1 activity remained unchanged despite a twofold increased mRNA level after n-3 PUFA feeding. Skeletal muscle FA oxidation was less affected by dietary n-3 PUFA, and the stimulatory effect was found only in peroxisomes. Dietary intake of n-3 PUFA was followed by increased acyl-CoA oxidase activity (48%, P < 0.05) and mRNA level (83%, P < 0.05) in skeletal muscle. The increased FA oxidation after n-3 PUFA supplementation of the high-fat diet was accompanied by lower plasma leptin concentration (-38%, P < 0.05) and leptin mRNA expression (-66%, P < 0.05) in retroperitoneal adipose tissue, and elevated hepatic mRNA level for the leptin receptor Ob-Ra (140%, P < 0.05). Supplementation of the high-fat diet with n-3 PUFA enhanced in vivo insulin sensitivity, as shown by normalization of the glucose infusion rate during euglycemic hyperinsulinemic clamp. Our results indicate that the hypotriglyceridemic effect of dietary n-3 PUFA is associated with stimulation of FA oxidation in the liver and to a smaller extent in skeletal muscle. This may ameliorate dyslipidemia, tissue lipid accumulation, and insulin action, in spite of decreased plasma leptin level and leptin mRNA in adipose tissue.

The purpose of this work was to study the effects of high environmental exposure to polychlorinated biphenyls (PCBs) and other organochlorines on the thyroid. Thyroid volume, hypoechogenicity and nodules (by ultrasound), presence of antithyroid peroxidase (anti-TPO) antibodies, and abnormal thyroid-stimulating hormone (TSH) levels in serum (by radioimmunoassay) were examined in 101 adults from the PCB-polluted area in 360 controls. Serum levels of PCBs, hexachlorobenzene, gamma-hexachlorocyclohexane (HCH), p,p'-DDT(1,1,1-trichloro-2,2'-bis(p-chlorophenyl)ethane), and p,p'-DDE(1,1-dichloro-2,2'-bis(p-chlorophenyl)ethene) were measured by high-resolution gas chromatography. Very high levels of PCBs were found in the polluted area (7300 +/- 871 ng/g lipids) compared with controls (2045 +/- 147 ng/g). Positive correlations (P < 0.001) were found between the levels of all organochlorines and their total except for hexachlorocyclohexane (HCH). In the polluted area, the highest thyroid volumes (18.7 +/- 2.32 mL; mean +/- SE) were clustered among 23 subjects (17 males and six females) with PCB levels above 10,000 ng/g (range 10,000-58,667 ng/g). In the remaining 438 subjects the thyroid volume was 14.2 +/- 0.29 mL. These data suggest that there might be a threshold serum PCB level of approximately 10,000 ng/g that may influence the thyroid volume. A two-way ANOVA showed that all thyroid volumes in the polluted area were significantly higher (P < 0.001) than in the control area. In males from the polluted area, the frequencies of thyroid hypoechogenicity, thyroid nodules, positive anti-TPO, and abnormal TSH level were higher than in males from the control area, whereas such differences were not observed in females. Increased thyroid volume and indicators of potential thyroid dysfunction were associated with long-term environmental exposure to PCBs. These effects on the thyroid were confined to subjects with PCB levels above 10,000 ng/g of lipid (thyroid volume) and to males from the polluted area (thyroid hypoechogenicity, thyroid nodules, positive anti-TPO, and abnormal TSH).

Hypertriglyceridaemia is an important risk factor for coronary heart disease, especially in the context of the insulin resistance syndrome where it often occurs with hypertension. The two phenotypes are also associated in the hereditary hypertriglyceridaemic (hHTg) rat. The aim of this study was to map quantitative trait loci that affect plasma triglyceride concentration in the hHTg rat and determine whether they co-localize with loci for blood pressure. Second filial generation progeny (n=189) from a cross of the hHTg rat with the Brown Norway rat were phenotyped for fasting plasma triglyceride, glucose and insulin concentrations, and direct unrestrained resting blood pressure. A partial genome-scan was conducted using 153 microsatellite markers that were polymorphic between the two strains. A major locus (lod score 6.5) influencing plasma triglyceride concentration in a co-dominant fashion was mapped to chromosome 4 between D1Mit 5 and D1Mit17. Chromosome 8 contained multiple peaks with a lod score greater than 4.0 influencing triglyceride concentration. Importantly, none of the triglyceride loci had an effect on blood pressure. The triglyceride locus on chromosome 4 co-localized with a locus for fasting plasma insulin (lod score 4.1), although the effect on insulin concentration was in the opposite direction to that on triglyceride. We have mapped the major loci that affect plasma triglyceride concentration in the hHTg rat. These loci do not influence blood pressure suggesting that these commonly associated phenotypes of the insulin resistance syndrome are not be due to pleiotropic effects of the same gene(s).

Increased oxidation of carbohydrates and free fatty acids is a well-known phenomenon during cold stress. Nevertheless, sources of the fuels used have not been fully clarified as yet. Thus, the aim of our study was to evaluate the effect of acute cold exposure on lipid and carbohydrate metabolism in human subcutaneous adipose tissue and to identify the possible regulatory mechanisms involved. Ten volunteers were exposed for 30 min to an ambient temperature of 4 degrees C. Interstitial metabolism was assessed with the aid of the microdialysis technique. Lipolysis intensity was evaluated from changes of glycerol concentration in plasma and in dialysate. Cold exposure induced a significant increase of glycerol concentration both in plasma (by 199 +/- 16%, p < 0.01) and in dialysate (by 308 +/- 58%, p < 0.001). No changes in glucose concentration were found whether in plasma or in the dialysate. Ethanol concentration in dialysate increased (148 +/- 15%, p < 0.01), indicating a slower blood flow in the subcutaneous region. Plasma concentrations of various gluco- and/or lipid-regulatory hormones remained unaffected by the cold exposure, except for norepinephrine, which rose about threefold (309 +/- 41%, p < 0.001). The data indicate an important role for subcutaneous adipose tissue in mobilization of free fatty acids during cold exposure. This process seems to be regulated by the sympathetic nervous system, whereas hormones involved in the regulation of lipid metabolism, such as epinephrine, insulin, cortisol, and growth hormone, may play a less significant role-at least under the conditions studied.

UNLABELLED A new Biorex molecule, BRX-220, has been shown to be effective in animal models of diabetic neuro- and retinopathy. Recent in vitro studies showed that it might also have an insulin-sensitizing action. Therefore, the effect of BRX-220 on insulin sensitivity was compared with the action of pioglitazone (PGZ) in high fat (HF) diet-induced insulin resistance (IR) of rats. METHODS Male Wistar rats were fed for 3 weeks a standard chow (PD) or the HF (70-cal%) diet. The HF-fed rats were also given daily BRX-220 (20 mg/kg BW) or PGZ (6 mg/kg BW) by gavage. In vivo insulin action was assessed by the euglycemic hyperinsulinemic clamp. Glucose, insulin, FFA, triglyceride (TG), and glycerol levels in blood were also measured, as well as tissue TG content. RESULTS Increased levels of fed TG in circulation after HF diet (PD: 2.0+/-0.2 vs. HF: 5.0+/-0.8 mmol/L) were partially corrected by BRX-220 (HF + BRX: 3.8+/-0.3) and normalized by PGZ (HF + PGZ: 2.6+/-0.3). Both molecules prevented the increase in fed serum FFA levels after HF diet (PD: 0.5+/-0.06; HF: 1.8+/-0.2 mmol/L), with a more pronounced effect of PGZ (HF + BRX: 1.2+/-0.1; HF + PGZ: 0.7+/-0.06). Tissue TG levels increased significantly in response to HF feeding in both liver (HF: 16+/-3.0; PD: 6.4+/-1.1 micromol/g) and skeletal muscle (HF: 7.7+/-1.2; PD: 2.4+/-0.4). This increase was completely normalized by both agents in the liver (HF + BRX: 8.8+/-0.8; HF + PGZ: 8.8+/-1.0), and only partially in the skeletal muscles. HF diet-induced in vivo IR (PD: 25.4+/-0.5; HF: 15.7+/-0.5 mg/kg/min) was significantly reduced by BRX-220 (HF + BRX: 18.7+/-0.3) and PGZ (HF + PGZ: 22.8+/-0.4) treatment. CONCLUSIONS (1) Subchronic administration of BRX-220 leads to an improvement of in vivo insulin action. (2) This insulin-sensitizing effect is, however, not as pronounced as that of PGZ. (3) It is accompanied by a decrease of circulating TG and FFA levels in the postprandial state and (4) by lower TG content in liver and skeletal muscle.

The objective of this study was to answer the question whether thyroid volume in adolescent siblings of similar age and a life-long sufficient iodine intake is uniform. If different, it would indicate that genetic or environmental factors unrelated to iodine intake can influence thyroid growth. We measured thyroid volume by ultrasound in: (1) 251 sibling pairs (SP) and 19 sibling triads 10 to 18 years of age. The age range of each SP was less than 24 months and of each triad less than 42 months; (2) 28 monozygotic and 13 dizygotic sets of twins 7 to 18 years of age. The sibling pairs were retrospectively divided into 3 groups irrespective of age (thyroid volume as means+/-S.E. mL/m2). Group 1: 159 pairs with low thyroid volume in both siblings; mean thyroid volume of each pair less than 5.00 mL/m2 (3.96+/-0.05, median 4.08, range 2.07-4.98); group 2: 69 pairs with high thyroid volume in both siblings; mean thyroid volume greater than 5.00 mL/m2 (5.85+/-0.12, median 5.57, range 5.03-11.02); group 3: 23 pairs with low thyroid volume in 1 sibling (3.53+/-0.15, median 3.53, range 1.71-4.91) and high thyroid volume in another (7.36+/-0.23, median 7.18, range 5.96-10.30). The majority of triads, monozygotic, and dizygotic twins resembled group 1, a few resembled group 2, and only 3 triads and 1 set of dizygotic twins resembled group 3. Among monozygotic twins, there was no pair with a strikingly discordant thyroid volume and only 1 such pair was found among dizygotic twins. In monozygotic twins, the thyroid volume was almost identical (mean difference 0.34+/-0.06 mL/m2) and significantly less (p0.012) than in dizygotic twins (0.9+/-0.25 mL/m2). Among 502 children of 251 sibling pairs the frequency of high thyroid volume (5.00 mL/m2) was greater in girls (103/279, 36.9%, p0.01) than in boys (49/223, 22.0%). The same was true for the frequency of hypoechogenicity (42/279 or 15.0% in girls vs. 12/223 or 5.4% in boys; p0.01). The frequency of hypoechogenicity in both sexes of the combined groups 2 and 3 (40/186, 21.5%) was higher (p0.001) than in group 1 (14/316, 4.4%). All siblings examined lived in a common household with their parents, eating the same daily meals at home and school. Our results suggest that the observed differences in thyroid volume of siblings were not related to iodine intake, but to other factors, eg, genetic and environmental. It is not clear whether the children with high thyroid volume and increased frequency of hypoechogenicity should be included into the recently recommended range of normal thyroid volume for adolescents.

The fatty acid (FA) compositions of liver and skeletal muscle structural lipids, overall phospholipids and phosphatidylcholine, and triglycerides (TG) were determined in the hereditary hypertriglyceridemic (HTG) rat, a nonobese animal model of the insulin resistance syndrome. Four groups of HTG rats and four groups of control animals were fed equal-energy diets for two weeks: basal (B), high-sucrose (HS), or fish oil-supplemented basal (BFO) or high-sucrose (HSFO) diets. In the liver of HTG rats, a decrease of n-6 long-chain polyunsaturated FA (PUFA), especially in 20:4n-6, in comparison with controls was found. Moreover, a concomitant accumulation of 18:2n-6 in structural lipids was observed. These differences were more pronounced in liver than in skeletal muscle. HS feeding raised the proportion of 18:1n-9 and decreased 18:2n-6 in lipid fractions. In both tissues and in both strains, the amounts of long-chain n-3 PUFA, as well as the level of total C20-22 PUFA, went up after fish oil feeding. However, the effects were somewhat less pronounced in the HTG rats. The increase in n-3 PUFA occurred mainly at the expense of reduced levels of 18:2n-6 in structural lipids and of 18:1n-9 in triglycerides. These changes were associated, in companion studies reported in this volume, with improved insulin action in HTG rats. In conclusion, the FA composition in lipid subclasses of HTG rats differs significantly from the controls mainly in liver structural lipids, suggesting the impairment of PUFA desaturation. Dietary change effected a similar modulation of FA profile across both strains, with fish oil increasing the levels of long-chain PUFA toward control values in the NTG rats. The HTG rat thus provides an interesting animal model for the study of impaired fatty acid metabolism.

Retinoic acid receptor alpha (RAR alpha) expression and RAR binding characteristics were investigated in the liver of rats with high-sucrose (HS) diet-induced insulin resistance. Animals were fed a basal (B) or HS (63 cal%) diet with or without fish oil (FO) (30% w/w of total fatty acids) for two weeks. A significant augmentation (p < 0.01) in the RAR alpha mRNA accumulation in rats fed HS diet when compared to rats fed B diet was demonstrated. In comparison with rats fed B + FO diet, a significant increase (p < 0.005) in the RAR alpha expression was found in rats fed HS + FO diet. In [3H]-retinoic acid (RA) binding studies, Scatchard plots confirmed a significant increase (p < 0.05) in the RAR maximal binding capacity (Bmax) only in rats fed HS + FO diet when compared to rats fed B diet. No significant changes in the association constant (Ka) were found among the groups when compared to rats fed B diet. In contrast to RAR alpha, a significant decrease (p < 0.005) in nuclear thyroid hormone receptor alpha 1 (TR alpha 1) expression was found in rats fed HS diet when compared to rats fed B diet. A significant decrease (p < 0.05) in the TR alpha 1 expression was also detected in rats fed HS + FO diet in comparison with rats fed B + FO diet. In addition, an analogous pattern in the expression of the TR isoform (TR alpha 2) was evaluated as well. In conclusion, the high-sucrose diet-induced insulin resistance might be associated with an increased RAR alpha expression and RAR population, and also with a decreased TR alpha 1 and TR alpha 2 mRNA accumulation.

Hypertriglyceridemia is closely linked to insulin resistance. Increased dietary intake of n - 3 polyunsaturated fatty acids reverses both hypertriglyceridemia and insulin resistance. To evaluate molecular mechanisms responsible for the hypotriglyceridemic effect of n - 3 polyunsaturated fatty acids, the expression of genes for lipogenic enzymes in liver and white and brown adipose tissue was estimated in hereditary hypertriglyceridemic rats which underwent an euglycemic hyperinsulinemic clamp. Before the clamp, animals were fed a basal or a high (63%) sucrose diet with or without fish oil for two weeks. Results were compared to data obtained from control animals subjected to the identical protocol. In hereditary hypertriglyceridemic rats, gene expression for malic enzyme was increased in liver and in brown adipose tissue but not in white adipose tissue. The high sucrose diet raised malic enzyme mRNA levels in liver of both hereditary hypertriglyceridemic and control rats, and this effect was more pronounced in brown adipose tissue. Supplementing the high sucrose diet with fish oil led to a suppression of malic enzyme gene expression in liver and brown adipose tissue of control rats. However, this inhibitory effect was not as pronounced in the hereditary hypertriglyceridemic rats. Raised levels of fatty acid synthase mRNA in liver and brown adipose tissue of control rats fed high sucrose diet were suppressed by consumption of diet high in n - 3 fatty acids. On the other hand, in hereditary hypertriglyceridemic rats fed high sucrose diet, fish oil supplementation failed to suppress increased levels of fatty acid synthase mRNA in liver and in brown adipose tissue. It appears that hereditary hypertriglyceridemic rats have elevated levels of mRNA for lipogenic enzymes in liver and brown adipose tissue and dietary control leading to an alteration of hypertriglyceridemia influences gene expression of lipogenic enzymes only under special dietary circumstances.