Thyroid volume, iodine intake, autoimmune thyroid disorders, inborn factors, and endocrine disruptors: twenty-year studies of multiple effects puzzle in Slovakia.

OBJECTIVE: The aim of this study was to evaluate multiple interrelations between several endogenous and exogenous effects and the thyroid volume and function in large groups of children, adolescents, and adults with a sufficient whole life intake of the iodine. SUBJECTS AND METHODS: The data were obtained either by cross sectioned or longitudinal studies in a total of 4998 children and adolescents (aged 7 to 17 years) and 2501 adults (1071 males and 1430 females aged 20-75 years). Thyroid volume (ThV) was measured by ultrasound, antibodies, and hormones by electrochemiluminiscent immunoassay, and endocrine disruptors (EDs, polychlorinated biphenyls-PCB, dichlorodiethyl-ichloroethylene-DDE, and hexachlorobenzene-HCB) by high resolution gas chromatography/mass spectrometry. RESULTS: 1. In large groups of boys and girls of age 7, 10, 13 or 17 years, the ThV was significantly higher in the 10th decile than in pooled nine lower deciles. Moreover, in 17-year old subjects significantly higher prevalence of hypoechogenicity by ultrasound, positive thyroperoxidase antibodies (TPOab), and increased thyrotropin (TSH) levels were found in the 10th decile. 2. In a small group of children, some individuals revealed consistently higher ThV during the whole 7-year follow-up period irrespective of supplementation with iodine. 3. In 325 sibling pairs of age 10-19 years, born within three years, three groups with different ThV/m2 of body surface were distinguished: Group A (183 pairs having both ThVs small), Group B (103 pairs having both ThVs large); Group C (33 pairs having one ThV small and the other one large). Similar aggregation of ThVs in three groups was observed in 13 pairs of discordant twins and 19 sibling triads in which all the siblings were born within four years. 4. In 42 concordant twins, several pairs had ThV nearly twice as high (in terms of both plain ThV or ThV/m2 of the body surface) as several other pairs of the same age which is assumed to be a result of a genetic background. 5. In large cohorts of males and females, a highly significant positive correlation was found between the ThV and high level of TPOab on one side and EDs on the other side. However, in nearly the same numbers of subjects with low TPOab, negative correlation was seen between ThV and disruptors. These observations may apparently support the synergic effect of the autoimmunity and EDs on the thyroid function. CONCLUSIONS: Several cases of an excessive thyroid growth in the iodine replenished children, adolescents, and adults may apparently result from the autoimmune thyroiditis, probably induced by immunogenic action of iodine in presumably disposed individuals. However, in some cases even simultaneous participation of EDs can not be excluded. Some observations have also suggested that excessive thyroid growth in the iodine replenished adolescent and adult population which was equally exposed to disruptors may also result from other reasons as the unfavorable hereditary background.

Comparison of the extrapancreatic action of gamma-linolenic acid and n-3 PUFAs in the high fat diet-induced insulin resistance [corrected].

OBJECTIVE: The effect of dietary borage oil (rich in the gamma-linolenic acid [GLA]) on insulin sensitivity and lipid metabolism was compared with that of fish oil (rich in n-3 polyunsaturated fatty acids [PUFAs]) in high fat (HF) diet-induced insulin resistance (IR) of rats. METHODS: Male Wistar rats were fed ad libitum for 3 weeks a standard laboratory chow (Controls) or high fat diet consisting of 70-cal % fat. In addition, a group of rats was fed high fat (HF) diet where a part of saturated fat was replaced with fish oil as a source of n-3 PUFAs (HF+FO), or borage oil as a source of GLA (HF+GLA). In vivo insulin action was assessed by the euglycemic hyperinsulinemic clamp. Glucose, insulin, free fatty acids (FFA), triglycerides (Tg) and glycerol levels in blood and tissue depots were also measured. RESULTS: Increased levels of Tg, FFA and glycerol in circulation after HF diet were accompanied by their raised accumulation in insulin sensitive tissues. FO feeding lowered the concentration of all lipids in serum and prevented their accumulation in both tissues. On the other hand GLA supplementation into the high fat diet did not suppress increased levels of Tg, FFA and glycerol in circulation and tissue depots as well. FO feeding significantly reduced HF diet-induced in vivo IR, while GLA supplementation did not improve the in vivo insulin sensitivity in HF diet induced insulin resistance. CONCLUSIONS: 1. Substitution of FO into the high fat diet led to an improvement of in vivo insulin action; 2. this insulin sensitizing effect of FO was accompanied by a decrease of circulating Tg, FFA and glycerol levels in the postprandial state and by a lower lipid content in liver and skeletal muscle. 3. on the opposite, GLA treatment failed to improve in vivo insulin action; and 4. was associated with an adverse effect on lipid levels both in circulation and tissue depots.

Insulin resistance in the hereditary hypertriglyceridemic rat is associated with an impairment of delta-6 desaturase expression in liver.

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.

Fatty acid composition in fractions of structural and storage lipids in liver and skeletal muscle of hereditary hypertriglyceridemic rats.

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.

Decreased glucose transporter protein (GLUT4) in skeletal muscle of hypertriglyceridaemic insulin-resistant rat.

Protein levels (Western blot) of the major glucose transporter isoform (GLUT4) were measured in skeletal muscles (quadriceps femoris) of an animal model of human metabolic syndrome X, i.e. the hereditary hypertriglyceridaemic (HTG) insulin-resistant rats fed various diets. The results were compared with the data obtained in normal Wistar rats which underwent the identical protocol. In HTG rats fed the basal diet (B) or high-sucrose diet (HS) (known to induce hypertriglyceridaemia and to impair insulin action), a decrease of GLUT4 protein levels (B: Control 100 +/- 3 vs HTG 46 +/- 5%, p < 0.005; HS: Control 80 +/- 9 vs HTG 49 +/- 3%, p < 0.005) was observed. Furthermore, marine fish oil (FO) rich in n-3 polyunsaturated fatty acids (PUFA), added to the basal diet (30 wt % of n-3 PUFA) reduced the GLUT4 protein levels (B: 100 +/- 3 vs B+FO: 42 +/- 4%, p < 0.005) in control rats to values similar to those found in HTG rats (B: 46 +/- 4%). However, dietary FO did not have any effect in HTG rats (49 +/- 3%). Feeding the high-sucrose diet supplemented with FO to both the control and HTG rats was followed by a further decrement of GLUT4 protein (Control 15 +/- 5 vs HTG 14 +/- 4%). In conclusions, a) the hereditary HTG rats had by about 50% lower GLUT4 protein levels in the quadriceps femoris muscle in comparison to normal Wistar rats; b) high-sucrose diet or raised dietary intake of n-3 PUFA did not further alter the number of glucose carriers in quadriceps femoris muscle in HTG rats and c) feeding the high-sucrose diet with higher proportion of n-3 PUFA was associated with an additional reduction of the GLUT4 protein level in this muscle.

Dietary fish oil and olive oil improve the liver insulin receptor tyrosine kinase activity in high sucrose fed rats.

In order to shed light on the possible beneficial effect of dietary unsaturated fatty acids on insulin binding, the effect of fish oil and olive oil administration on insulin binding, autophosphorylation and tyrosine kinase activity of partially purified liver insulin receptors were investigated. These data were confronted with the parameters of sugar and lipid metabolism (blood glucose, insulin and triglycerides), with liver plasma membrane fluidity and fatty acid composition. High sucrose feeding resulted in the elevation of blood glucose and triglyceride level, while the supplementation of animals with fish oil reduced that of triglycerides and olive oil that of insulin. Any significant changes between experimental groups were not detected either in insulin binding to partially purified liver insulin receptor nor in receptor autophosphorylation. However, the insulin stimulated tyrosine kinase activity towards an exogenous substrate (poly(Glu,Tyr)) was decreased by about 50% in the receptors solubilized from liver membranes of sucrose fed rats. Increased dietary intake of fish oil or olive oil restored the activity of insulin tyrosine kinase towards control values, half maximal effect being obtained at similar insulin concentration in all groups. Such improvement might be due to the induced increase of membrane fluidity by unsaturated fatty acids, and/or to the decrease of insulinemia.

HMG-CoA reductase activity in the liver of rats with hereditary hypertriglyceridemia: effect of dietary fish oil.

To assess the possible participation of liver microsomal 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in the hypocholesterolemic effect of fish oil (FO) in rats with hereditary hypertriglyceridemia (derived from the Wistar strain, obtained from VELAZ, Prague, Czech Rep.), male animals were fed a basal diet (BD) or a high sucrose diet (SD-63 cal %) with or without FO supplement (30 wt% n-3 polyunsaturated fatty acids) for 21 days. The feeding with high sucrose diet resulted in increased HMG-CoA reductase activity; (P < 0.05). However, FO added to the diet suppressed this stimulated enzymatic activity (919.05 +/- 76.86 vs. 614.05 +/- 48.53 pmol/min/mg prot.; P < 0.05) and decreased cholesterol (CH) content in both serum and the liver of HTG rats fed basal as well as sucrose diet; (P < 0.05). The results of the study demonstrated that the hypocholesterolemic effect of FO added to the diet was mediated under certain conditions, by affecting of HMG-CoA reductase activity and not only by its effect on specific receptors as demonstrated before.

Effect of dietary fish oil on 2-deoxy-D-3H glucose uptake in isolated adipocytes of rats fed various diets.

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.

Modulation of the hypolipidemic effect of fish oil by inhibition of adipose tissue lipolysis with acipimox, a nicotinic acid analog.

To assess the possible benefits of combined hypolipidemic therapy (acipimox+marine fish oil) on lipid and lipoprotein metabolism, male Wistar rats were fed for 14 days a high sucrose diet (70 cal% sucrose) alone or a high sucrose diet supplemented with acipimox (0.2 g/100 g diet) and/or fish oil (1 ml orally daily; 30 wt% of n-3 PUFA). Feeding a high sucrose diet increased (control: 61 +/- 6 vs HS: 110 +/- 8 nmol.min-1.mg-1, p < 0.001) the activity of acetyl CoA carboxylase in the liver, this was normalized by fish oil but not acipimox alone (HS+FO: 68 +/- 4; HS+ACI: 95 +/- 4; HS+ACI+FO: 71 +/- 2 nmol.min-1.mg-1). Increased triglyceride concentration in serum and muscle tissue (m. soleus and heart) of high sucrose-fed animals was suppressed equally by fish oil, acipimox, and/or both. The cholesterol-lowering effect of fish oil was also present in the liver (p < 0.005). The cholesterol-lowering action of acipimox was accompanied by the accumulation of cholesterol in the liver (p < 0.005), whereas the combination of acipimox+fish oil did not change the liver cholesterol content. After fish oil the LDL binding capacity of liver plasma membranes was increased 1.6-fold (p < 0.001). LDL receptor activity was significantly decreased in HS+ACI group (p < 0.05), but remained unchanged in HS+FO+ACI-fed animals. In summary, (a) the hypotriglyceridemic effect of fish oil in high sucrose-induced HTG is due to its inhibitory effects at the level of fatty acid synthesis; (b) decreased triglyceride production and output from the liver prevent triglyceride accumulation in muscle tissue; (c) the cholesterol-lowering action of acipimox but not fish oil was accompanied by an accumulation of cholesterol in the liver; (d) the latter phenomenon may be due to the opposite effects of both drugs on cholesterol catabolism via hepatic LDL receptors.

Muscle GLUT 4 protein levels and impaired triglyceride metabolism in streptozotocin diabetic rats. Effect of a high sucrose diet and fish oil supplementation.

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.

Anxiety management for persistent generalised anxiety.

A preliminary controlled investigation of the effectiveness of Anxiety Management as a treatment for generalised anxiety disorder (GAD) is described. Patients with a primary diagnosis of GAD, in which the current episode had lasted for at least 6 months but not more than 2 years, were included. Anxiety Management, a self-help treatment including procedures for managing somatic and cognitive symptoms, and for dealing with avoidance and low self-confidence, was given either immediately or after a 12-week waiting period. The average length of treatment was 8.7 sessions. Highly significant changes in anxiety, depression, and problem ratings were shown after treatment. These changes were replicated when the waiting list group had also received treatment, and gains were maintained by both groups for 6 months. Similar degrees of improvement and maintenance of change were shown in subgroups with and without minor depressive disorder or recurrent panic attacks.