Effect of Gestational Fish Oil Supplementation on Liver Metabolism and Mitochondria of Male and Female Rat Offspring Programmed by Maternal High-Fat Diet.

SCOPE: Perinatal maternal moderately high-fat diet (mHFD) is associated with obesity and fatty liver disease in offspring, and maternal fish oil (FO: n-3 PUFA source) supplementation may attenuate these disorders. This study evaluates the effects of FO given to pregnant rats fed a mHFD on the offspring's liver at weaning. METHODS AND RESULTS: Female Wistar rats receive an isoenergetic, control (CT: 10.9% from fat) or high-fat (HF: 28.7% from fat) diet before mating, and throughout pregnancy and lactation. FO supplementation (HFFO: 2.9% of FO in the HF diet) is given to one subgroup of HF dams during pregnancy. At weaning, male and female mHFD offspring display higher body mass, adiposity, and hepatic cellular damage, steatosis, and inflammation, accompanied by increased damaged mitochondria. FO does not protect pups from systemic metabolic alterations and partially mitigates hepatic histological damage induced by mHFD only in females. However, FO reduces mRNA expression of lipogenic genes, and mitochondrial damage, and modified mitochondrial morphology suggestive of early adaptations via mitochondrial dynamics. CONCLUSIONS: Gestational FO supplementation has limited beneficial effects on the damage caused by perinatal mHFD consumption in offspring's liver at weaning. However, FO imprinting effect on lipid metabolism and mitochondria may have beneficial long-term outcomes.

Maternal high-fat diet aggravates fructose-induced mitochondrial damage in skeletal muscles and causes differentiated adaptive responses on lipid metabolism in adult male offspring.

Maternal high-fat diet (HFD) is associated with metabolic disturbances in the offspring. Fructose is a highly consumed lipogenic sugar; however, it is unknown whether skeletal muscle of maternal HFD offspring respond differentially to a fructose overload. Female Wistar rats received standard diet (STD: 9% fat) or isocaloric high-fat diet (HFD: 29% fat) during 8 weeks before mating until weaning. After weaning, male offspring received STD and, from 120 to 150 days-old, they drank water or 15% fructose in water (STD-F and HFD-F). At 150th day, we collected the oxidative soleus and glycolytic extensor digitorum longus (EDL) muscles. Fructose-treated groups exhibited hypertriglyceridemia, regardless of maternal diet. Soleus of maternal HFD offspring showed increased triglycerides and monounsaturated fatty acid content, independent of fructose, with increased fatty acid transporters and lipogenesis markers. The EDL exhibited unaltered triglycerides content, with an apparent equilibrium between lipogenesis and lipid oxidation markers in HFD, and higher lipid uptake (fatty acid-binding protein 4) accompanied by enhanced monounsaturated fatty acid in fructose-treated groups. Mitochondrial complexes proteins and Tfam mRNA were increased in the soleus of HFD, while uncoupling protein 3 was decreased markedly in HFD-F. In EDL, maternal HFD increased ATP synthase, while fructose decreased Tfam predominantly in STD offspring. Maternal HFD and fructose induced mitochondria ultrastructural damage, intensified in HFD-F in both muscles. Thus, alterations in molecular markers of lipid metabolism and mitochondrial function in response to fructose are modified by an isocaloric and moderate maternal HFD and are fiber-type specific, representing adaptation/maladaptation mechanisms associated with higher skeletal muscle fructose-induced mitochondria injury in adult offspring.

Cinnamaldehyde treatment during adolescence improves white and brown adipose tissue metabolism in a male rat model of early obesity.

Early obesity is a serious health problem and nutritional therapeutic strategies during young age may improve health outcomes throughout life. Cinnamaldehyde, the major component of cinnamon, exhibits several beneficial metabolic effects. Here we tested the impact of cinnamaldehyde treatment during adolescence in a rat model of obesity programmed by early overnutrition, addressing white (WAT) and brown adipose tissue (BAT). After birth, litters were adjusted to 10 pups or 3 pups (small litter) to induce overfeeding and early obesity. On postnatal day 30, half of the small litter pups received cinnamaldehyde (40 mg per kg of body mass per day) for 30 days. The animals were studied at the end of the treatment at 60 days of age and 4 months thereafter (180 days old). The early overfeeding programmed to higher epididymal WAT mass, adipocyte hypertrophy at both ages, and higher BAT mass associated with higher lipid accumulation in the long term. Cinnamaldehyde reduced the adipocyte hypertrophy associated with reduced lipogenesis machinery expression (Srebf1c, Acaca), while it stimulated oxidative ones (Ppargc1a, Fgf21) in WAT, and increased BAT thermogenesis markers (Ppara, Fgf21, Ucp1). In the long term, cinnamaldehyde treatment reprogrammed the metabolism leading to a diminished WAT adipocyte size, accompanied by reduced expression of lipogenesis-related genes (Pparg, Dgat2). In BAT, cinnamaldehyde led to reduced lipogenesis marker expression (Pparg, Lpl) associated with the reduced whitening phenotype, and a robust increase in Fgf21 expression. These results suggest that cinnamaldehyde intake during adolescence has long-lasting benefits in WAT and BAT metabolism, reinforcing its potential as a reprogramming nutraceutical in the treatment of childhood obesity.

The role of thyroid hormone in metabolism and metabolic syndrome.

Metabolic syndrome (MetS) and thyroid dysfunction are common in clinical practice. The objectives of this review are to discuss some proposed mechanisms by which thyroid dysfunctions may lead to MetS, to describe the bidirectional relationship between thyroid hormones (THs) and adiposity and finally, to resume a list of recent studies in humans that evaluated possible associations between thyroid hormone status and MetS or its clinical components. Not solely THs, but also its metabolites regulate metabolic rate, influencing adiposity. The mechanisms enrolled are related to its direct effect on adenosine triphosphate (ATP) utilization, uncoupling synthesis of ATP, mitochondrial biogenesis, and its inotropic and chronotropic effects. THs also act controlling core body temperature, appetite, and sympathetic activity. In a bidirectional way, thyroid function is affected by adiposity. Leptin is one of the hallmarks, but the pro-inflammatory cytokines and also insulin resistance impact thyroid function and perhaps its structure. MetS development and weight gain have been positively associated with thyroid-stimulating hormone (TSH) in several studies. Adverse glucose metabolism may be related to hyperthyroidism, but also to reduction of thyroid function or higher serum TSH, as do abnormal serum triglyceride levels. Hypo- and hyperthyroidism have been related to higher blood pressure (BP), that may be consequence of genomic or nongenomic action of THs on the vasculature and in the heart. In summary, the interaction between THs and components of MetS is complex and not fully understood. More longitudinal studies controlling each of all confounding variables that interact with endpoints or exposure factors are still necessary.

Treatment with cinnamaldehyde reduces the visceral adiposity and regulates lipid metabolism, autophagy and endoplasmic reticulum stress in the liver of a rat model of early obesity.

Nutrition at early stages of life contributes to the alarming incidence of childhood obesity, insulin resistance and hepatoesteatosis. Cinnamaldehyde, major component of cinnamon, increases insulin sensitivity and modulates adiposity and lipid metabolism. The aim of this study was to analyze the impact of cinnamaldehyde treatment during adolescence in a rat model of early obesity. Litter size reduction was used to induce overfeeding and early obesity. At postnatal day 30 (adolescence), the male Wistar rats received cinnamaldehyde by gavage (40 mg/kg of body weight/day) for 29 days and were studied at the end of treatment at 60 days old or 4 months thereafter (180 days old). At 60 days of age, the treatment with cinnamaldehyde promoted reduced visceral adiposity, serum triacylglycerol, and attenuation of energy efficiency and insulin resistance. In the liver, it reduced lipid synthesis, stimulated autophagy and reduced ER stress. At 180 days of age, animals treated with cinnamaldehyde during the adolescence exhibited normalization of visceral adiposity and energy efficiency, and attenuation of hyperphagia, serum hypertriglyceridemia and hepatic triacylglycerol content, with molecular markers indicative of reduced hepatic synthesis. However, the beneficial effect observed at 60 days of age on glucose homeostasis, autophagy and ER stress was lost. Therefore, the cinnamaldehyde supplementation during the adolescence has short- and long-term metabolic beneficial effects, highlighting its potential as an adjuvant in the treatment of early obesity.

Neuromedin B receptor disruption impairs adipogenesis in mice and 3T3-L1 cells.

Neuromedin B, a bombesin-like peptide, and its receptor, are expressed in white adipose tissue with undefined roles. Female mice with disruption of neuromedin B receptor (NB-R) exhibited partial resistance to diet-induced obesity leading to our hypothesis that NB-R is involved in adipogenesis. Here, we showed that adipose stem/stromal cells (ASC) from perigonadal fat of female NB-R-knockout mice, exposed to a differentiation protocol in vitro, accumulated less lipid (45%) than wild type, suggesting reduced capacity to differentiate under adipogenic input. To further explore mechanisms, preadipocytes 3T3-L1 cells were incubated in the presence of NB-R antagonist (PD168368) during the first 3 days in culture. Cells were analyzed in the end of the treatment (Day 3) and later when fully differentiated (Day 21). NB-R antagonist induced lower number of cells at day 3 and 21 (33-39%), reduced cell proliferation at day 3 (-53%) and reduced lipid accumulation at day 21 (-86%). The mRNA expressions of several adipocyte differentiation markers were importantly reduced at both days: Cebpb and Pparg and Fabp4, Plin-1 and Adipoq, and additionally Lep mRNA at day 21. The antagonist had no effect when incubated with mature 3T3-L1 adipocytes. Therefore, genetically disruption of NB-R in mice ASC or pharmacological antagonism of NB-R in 3T3-L1 cells impairs adipogenesis. The mechanisms suggested by results in 3T3-L1 cells involve reduction of cell proliferation and of early gene expressions, leading to decreased number of mature adipocytes. We speculate that NB-R antagonism may be useful to limit the increase in adiposity due to pre-adipocyte differentiation.

Maternal cinnamon intake during lactation led to visceral obesity and hepatic metabolic dysfunction in the adult male offspring.

PURPOSE: Studies with foods, known to promote health benefits in addition to the nutritive value, show that their consumption by pregnant and/or lactating females could induce negative outcomes to the offspring. It is well characterized that cinnamon intake promotes benefits to energy homeostasis. The present study aimed to analyze the effects of the consumption of an aqueous extract of cinnamon by lactating female rats on the endocrine-metabolic outcomes in the adult offspring. METHODS: Lactating dams (Wistar rats) were supplemented with cinnamon aqueous extract (400 mg/kg body weight/day) for the entire lactating period. The male adult offspring were evaluated at 180 days old (CinLac). RESULTS: The offspring presented visceral obesity (P = 0.001), hyperleptinemia (P = 0.002), and hyperinsulinemia (P = 0.016). In the liver, CinLac exhibited reduced p-IRß (P = 0.018) suggesting insulin resistance. However, phosphorylation of IRS1 (P = 0.041) and AKT (P = 0.050) were increased. JAK2 (P = 0.030) and p-STAT3 (P = 0.015) expressions were higher, suggesting that the activation of IRS1/AKT in the CinLac group could have resulted from the increased activation of leptin signaling. Although we observed no changes in the gluconeogenic pathway, the CinLac group exhibited lower hepatic glycogen content (P = 0.005) accompanied by increased p-GSK3ß (P = 0.011). In addition, the CinLac group showed increased hepatic triacylglycerol content (P = 0.049) and a mild steatosis (P = 0.001), accompanied by reduced PPARα mRNA expression (P = 0.005). CONCLUSION: We conclude that maternal intake of aqueous extract of cinnamon induces long-term molecular, metabolic, and hormonal changes in the adult progeny, including visceral obesity, higher lipid accumulation, and lower glycogen content in the liver.

Maternal high-fat diet consumption induces sex-dependent alterations of the endocannabinoid system and redox homeostasis in liver of adult rat offspring.

Maternal diet plays a critical role in health development. Perinatal overnutrition induces metabolic dysfunctions and obesity in the offspring. Obesity is associated with endocannabinoid system (ECS) over activation and oxidative stress. Liver ECS activation induces hepatic steatosis, inflammation and fibrosis while the antagonism of cannabinoid receptors ameliorates these alterations. Here, we investigated the effect of perinatal maternal high-fat diet (HF, 29% of calories as fat) on the ECS and antioxidant system in liver of male and female adult rat offspring (180 days old). Maternal HF diet increased hepatic cannabinoid receptors, ECS metabolizing enzymes and triglyceride content, with male offspring more affected. ECS changes are likely independent of estradiol serum levels but associated with increased hepatic content of estrogen receptor, which can stimulate the expression of ECS components. Differently, maternal HF diet decreased the activity of the antioxidant enzymes glutathione peroxidase, superoxide dismutase and catalase, and increased oxidative stress markers in both sexes. Alterations in the redox homeostasis were associated with mitochondria damage but not with liver fibrosis. Our data suggest that maternal HF diet induces ECS over activation in adulthood, and that male offspring are at higher risk to develop liver disease compared with female rats.

Thyroid Function Disruptors: from nature to chemicals.

The modern concept of thyroid disruptors includes man-made chemicals and bioactive compounds from food that interfere with any aspect of the hypothalamus-pituitary-thyroid axis, thyroid hormone biosynthesis and secretion, blood and transmembrane transport, metabolism and local action of thyroid hormones. This review highlights relevant disruptors that effect populations through their diet: directly from food itself (fish oil and polyunsaturated fatty acids, pepper, coffee, cinnamon and resveratrol/grapes), through vegetable cultivation (pesticides) and from containers for food storage and cooking (bisphenol A, phthalates and polybrominated diphenyl ethers). Due to the vital role of thyroid hormones during every stage of life, we review effects from the gestational period through to adulthood, including evidence from in vitro studies, rodent models, human trials and epidemiological studies.

Hepatic microvascular dysfunction and increased advanced glycation end products are components of non-alcoholic fatty liver disease.

BACKGROUND: This study aimed to investigate the pathophysiology of hepatic microcirculatory dysfunction in non-alcoholic fatty liver disease (NAFLD). METHODS: In Wistar rats, NAFLD model was induced by 20 weeks of high-fat diet (HFD) feeding. Rolling and adhesion of leukocytes and tissue perfusion in hepatic microcirculation were examined using in vivo microscopic and laser speckle contrast imaging (LSCI), respectively. Oxidative stress and inflamatory parameters were analysed by TBARs, catalase enzyme activity, RT-PCR and ELISA. The participation of advanced glycation end-products (AGE) and its receptor RAGE was evaluated by the measurement of gene and protein expression of RAGE by RT-PCR and Western-blot, respectively and by liver and serum quantification of fluorescent AGEs. RESULTS: Wistar rats fed high-fat diet (HFD) showed increase in epididymal and abdominal fat content, systolic arterial blood pressure, fasting blood glucose levels, hepatic triglycerides and cholesterol, and impairment of glucose and insulin metabolisms. Liver histology confirmed the presence of steatosis and ultrasound analysis revealed increased liver size and parenchymal echogenicity in HFD-fed rats. HFD causes significant increases in leukocyte rolling and adhesion on hepatic microcirculation and decrease in liver microvascular blood flow. Liver tissue presented increase in oxidative stress and inflammtion. At 20 weeks, there was a significantly increase in AGE content in the liver and serum of HFD-fed rats and an increase in RAGE gene expression in the liver. CONCLUSION: The increase in liver AGE levels and microcirculatory disturbances could play a role in the pathogenesis of liver injury and are key components of NAFLD.

Hypothyroidism Induces Hypophagia Associated with Alterations in Protein Expression of Neuropeptide Y and Proopiomelanocortin in the Arcuate Nucleus, Independently of Hypothalamic Nuclei-Specific Changes in Leptin Signaling.

BACKGROUND: Thyroid hormone and leptin are essential regulators of energy homeostasis. Both hormones stimulate energy expenditure but have opposite effects on appetite. The mechanisms behind food intake regulation in thyroid dysfunctions are poorly understood. It has been shown that hypothyroid rats exhibited impaired leptin anorexigenic effect and signaling in total hypothalamus, even though they were hypophagic. It was hypothesized that hypothyroidism modulates the expression of neuropeptides: orexigenic neuropeptide Y (NPY) and anorexigenic proopiomelanocortin (POMC), independently of inducing nuclei-specific changes in hypothalamic leptin signaling. METHODS: Adult male rats were rendered hypothyroid by administration of 0.03% methimazole in the drinking water for 21 days. Protein content of NPY, POMC, and leptin signaling (the signal transducer and activator of transcription 3 [STAT3] pathway) were evaluated by Western blot, and mRNA levels by real time reverse transcription polymerase chain reaction in arcuate (ARC), ventromedial (VMN), and paraventricular (PVN) hypothalamic nuclei isolated from euthyroid (eu) and hypothyroid (hypo) rats. Leptin anorexigenic effect was tested by recording food intake for two hours after intracerebroventricular (i.c.v.) administration of leptin. Statistical differences were considered significant at p ≤ 0.05. RESULTS: Hypothyroidism was confirmed by decreased serum triiodothyronine, thyroxine, and increased thyrotropin, in addition to increased levels of pro-TRH mRNA in PVN and Dio2 mRNA in the ARC of hypo rats. Hypothyroidism decreased body weight and food intake associated with decreased protein content of NPY and increased content of POMC in the ARC. Conversely, hypothyroidism induced central resistance to the acute anorexigenic effect of leptin, since while euthyroid rats displayed reduced food intake after leptin i.c.v. injection, hypothyroid rats showed no response. Hypothyroid rats exhibited decreased leptin receptor (ObRb) protein content in ARC and VMN but not in PVN nucleus. ObRb protein changes were concomitant with decreased phosphorylated STAT3 in the ARC, and decreased total STAT3 in VMN and PVN. However, hypothyroidism did not affect mRNA levels of Lepr or Stat3 in the hypothalamic nuclei. CONCLUSIONS: Experimental hypothyroidism induced a negative energy balance accompanied by decreased NPY and increased POMC protein content in the ARC, resulting in predominance of anorexigenic pathways, despite central leptin resistance and impairment of the leptin signaling cascade in a nuclei-specific manner.

High levels of circulating triiodothyronine induce plasma cell differentiation.

The effects of hyperthyroidism on B-cell physiology are still poorly known. In this study, we evaluated the influence of high-circulating levels of 3,5,3'-triiodothyronine (T3) on bone marrow, blood, and spleen B-cell subsets, more specifically on B-cell differentiation into plasma cells, in C57BL/6 mice receiving daily injections of T3 for 14 days. As analyzed by flow cytometry, T3-treated mice exhibited increased frequencies of pre-B and immature B-cells and decreased percentages of mature B-cells in the bone marrow, accompanied by an increased frequency of blood B-cells, splenic newly formed B-cells, and total CD19(+)B-cells. T3 administration also promoted an increase in the size and cellularity of the spleen as well as in the white pulp areas of the organ, as evidenced by histological analyses. In addition, a decreased frequency of splenic B220(+) cells correlating with an increased percentage of CD138(+) plasma cells was observed in the spleen and bone marrow of T3-treated mice. Using enzyme-linked immunospot assay, an increased number of splenic immunoglobulin-secreting B-cells from T3-treated mice was detected ex vivo. Similar results were observed in mice immunized with hen egg lysozyme and aluminum adjuvant alone or together with treatment with T3. In conclusion, we provide evidence that high-circulating levels of T3 stimulate plasma cytogenesis favoring an increase in plasma cells in the bone marrow, a long-lived plasma cell survival niche. These findings indicate that a stimulatory effect on plasma cell differentiation could occur in untreated patients with Graves' disease.

Non-classic thyroid hormone signalling involved in hepatic lipid metabolism.

Thyroid hormones are important modulators of lipid metabolism because the liver is a primary hormonal target. The hypolipidaemic effects of thyroid hormones result from the balance between direct and indirect actions resulting in stimulation of lipid synthesis and lipid oxidation, which favours degradation pathways. Originally, it was believed that thyroid hormone activity was only transduced by alteration of gene transcription mediated by the nuclear receptor thyroid hormone receptors, comprising the classic action of thyroid hormone. However, the discovery of other effects independent of this classic mechanism characterised a new model of thyroid hormone action, the non-classic mechanism that involves other signalling pathways. To date, this mechanism and its relevance have been intensively described. Considering the increasing evidence for non-classic signalling of thyroid hormones and the major influence of these hormones in the regulation of lipid metabolism, we reviewed the role of thyroid hormone in cytosolic signalling cascades, focusing on the regulation of second messengers, and the activity of effector proteins and the implication of these mechanisms on the control of hepatic lipid metabolism.

Thyroid hormone regulation of Sirtuin 1 expression and implications to integrated responses in fasted mice.

Sirtuin 1 (SIRT1), a NAD(+)-dependent deacetylase, has been connected to beneficial effects elicited by calorie restriction. Physiological adaptation to starvation requires higher activity of SIRT1 and also the suppression of thyroid hormone (TH) action to achieve energy conservation. Here, we tested the hypothesis that those two events are correlated and that TH may be a regulator of SIRT1 expression. Forty-eight-hour fasting mice exhibited reduced serum TH and increased SIRT1 protein content in liver and brown adipose tissue (BAT), and physiological thyroxine replacement prevented or attenuated the increment of SIRT1 in liver and BAT of fasted mice. Hypothyroid mice exhibited increased liver SIRT1 protein, while hyperthyroid ones showed decreased SIRT1 in liver and BAT. In the liver, decreased protein is accompanied by reduced SIRT1 activity and no alteration in its mRNA. Hyperthyroid and hypothyroid mice exhibited increases and decreases in food intake and body weight gain respectively. Food-restricted hyperthyroid animals (pair-fed to euthyroid group) exhibited liver and BAT SIRT1 protein levels intermediary between euthyroid and hyperthyroid mice fed ad libitum. Mice with TH resistance at the liver presented increased hepatic SIRT1 protein and activity, with no alteration in Sirt1 mRNA. These results suggest that TH decreases SIRT1 protein, directly and indirectly, via food ingestion control and, in the liver, this reduction involves TRß. The SIRT1 reduction induced by TH has important implication to integrated metabolic responses to fasting, as the increase in SIRT1 protein requires the fasting-associated suppression of TH serum levels.

Central NPY-Y5 receptors activation plays a major role in fasting-induced pituitary-thyroid axis suppression in adult rat.

Neuropeptide Y (NPY) inhibits TRH neurons in fed state, and hypothalamic NPY higher expression during fasting has been proposed to be involved in fasting-induced suppression of the hypothalamus-pituitary-thyroid (HPT) axis. We investigated the role of central Y5 receptors in the control of thyrotropin (TSH) and thyroid hormone (TH) secretion. Fed and fasting rats received twice daily central injections (3rd ventricle) of Y5 receptor antagonist (CGP71683; 15nmol/rat) for 72h. Fasted rats also received a single central injection of CGP71683 (15nmol/rat) at the end of 72h of fasting. In fed rats, Y5 receptor blockade reduced total food intake by 32% and body mass by almost 10% (p<0.01), corroborating the role of this receptor in food intake control. 72h-fasted rats exhibited a 4-fold increase in serum TSH (p<0.001), 1h after a single injection of Y5 antagonist. Also with multiple injections during 72h of fasting, Y5 blockade resulted in activation of thyroid axis, as demonstrated by a 3-times rise in serum T4 (p<0.001), accompanied by unchanged TSH and T3. In fed rats, the chronic central administration of CGP71683 resulted in reduced total serum T4 without changes in free T4 and TSH. Serum leptin and PYY were not altered by the NPY central blockade in both fed and fasted rats, suggesting no role of these hormones in the alterations observed. Therefore, the inhibition of central Y5 neurotransmission resulted in activation of thyroid axis during fasting suggesting that NPY-Y5 receptors contribute to fasting-induced TSH and TH suppression.

Thyroid hormone contributes to the hypolipidemic effect of polyunsaturated fatty acids from fish oil: in vivo evidence for cross talking mechanisms.

n-3 polyunsaturated fatty acids (n-3 PUFA) from fish oil (FO) exert important lipid-lowering effects, an effect also ascribed to thyroid hormones (TH) and TH receptor ß1 (TRß1)-specific agonists. n-3 PUFA effects are mediated by nuclear receptors, such as peroxisome proliferator-activated receptors (PPAR) and others. In this study, we investigated a role for TH signaling in n-3 PUFA effects. Euthyroid and hypothyroid adult rats (methimazole-treated for 5 weeks) received FO or soybean oil (control) by oral administration for 3 weeks. In euthyroid rats, FO treatment reduced serum triglycerides and cholesterol, diminished body fat, and increased protein content of the animals. In addition, FO-treated rats exhibited higher liver expression of TRß1 and mitochondrial α-glycerophosphate dehydrogenase (mGPD), at protein and mRNA levels, but no alteration of glutathione S-transferase or type 1 deiodinase. In hypothyroid condition, FO induced reduction in serum cholesterol and increase in body protein content, but lost the ability to reduce triglycerides and body fat, and to induce TRß1 and mGDP expression. FO did not change PPARα liver abundance regardless of thyroid state; however, hypothyroidism led to a marked increase in PPARα liver content but did not alter TRß1 or TRα expression. The data suggest that part of the effect of n-3 PUFA from FO on lipid metabolism is dependent on TH signaling in specific steps and together with the marked upregulation of PPARα in liver of hypothyroid rats suggest important in vivo consequences of the cross-talking between those fatty acids and TH pathways in liver metabolism.

Resveratrol reduces lipid peroxidation and increases sirtuin 1 expression in adult animals programmed by neonatal protein restriction.

Resveratrol (Res) has been associated with protective effects against oxidative stress. This study evaluated the effect of Res over lipid peroxidation, antioxidant defense, hepatic sirtuin 1 (SIRT1), which up-regulates antioxidant enzymes, and copper/zinc superoxide dismutase (Cu/Zn SOD) in adult offspring whose mothers were protein restricted during lactation. Lactating Wistar rats were divided into control (C) group, which were fed a normal diet (23% protein), and low-protein and high-carbohydrate (LPHC) group, which were fed a diet containing 8% protein. After weaning (21 days), C and LPHC offspring were fed a normal diet until they were 180 days old. At the 160th day, animals were separated into four groups as follows: control, control+Res, LPHC, and LPHC+Res. Resveratrol was given for 20 days (30  mg/kg per day by gavage). LPHC animals showed a higher total antioxidant capacity (TAC) without change in lipid peroxidation and SIRT1 expression. The treatment with Res increased TAC only in the control group without effect on lipid peroxidation and SIRT1. LPHC animals treated with Res had lower lipid peroxidation and higher protein and mRNA expression of SIRT1 without any further increase in TAC. No significant difference in liver Cu/Zn SOD expression was observed among the groups. In conclusion, maternal protein restriction during lactation programs the offspring for a higher antioxidant capacity, and these animals seem to respond to Res treatment with a lower lipid peroxidation and higher hepatic SIRT1 expression that we did not observe in the Res-treated controls. It is probable that the protective effect can be attributed to Res activating SIRT1, only in the LPHC-programmed group.

Female mice target deleted for the neuromedin B receptor have partial resistance to diet-induced obesity.

Previous studies have proposed a role for neuromedin B (NB), a bombesin-like peptide, in the control of body weight homeostasis. However, the nature of this role is unclear. The actions of NB are mediated preferentially by NB-preferring receptors (NBRs). Here we examined the consequences of targeted deletion of NBRs in female mice on body weight homeostasis in mice fed a normolipid diet (ND) or a high-fat diet (HFD) for 13 weeks. Body weight and food ingestion of neuromedin B receptor knockout (NBR-KO) mice fed a normolipid diet showed no difference in relation to wild-type (WT). However, the high-fat diet induced an 8.9- and 4.8-fold increase in body weight of WT and NBR-KO, respectively, compared to their controls maintained with a normolipid diet, even though the mice ingested the same amount of calories, regardless of genotype. Comparing mice fed the high-fat diet, NBR-KO mice accumulated approximately 45% less fat depot mass than WT, exhibited a lower percentage of fat in their carcasses (19.2 vs. 31.3%), and their adipocytes were less hypertrophied. Serum leptin and leptin mRNA in inguinal and perigonadal fat were lower in HFD NBR-KO than HFD WT, and serum adiponectin was similar among HFD groups and unaltered in comparison to ND-fed mice. HFD-fed WT mice developed glucose intolerance but not the HFD-fed NBR-KO mice, although they had similar glycaemia and insulinaemia. NBR-KO and WT mice on the normolipid diet showed no differences in any parameters, except for a trend to lower insulin levels. Therefore, disruption of the neuromedin B receptor pathway did not change body weight homeostasis in female mice fed a normolipid diet; however, it did result in partial resistance to diet-induced obesity.

Acute effects of endocannabinoid anandamide and CB1 receptor antagonist, AM251 in the regulation of thyrotropin secretion.

We examined the acute effects of endocannabinoid, anandamide, and of synthetic cannabinoid receptor antagonist, AM251[N-(piperidin-1-yl)-1-(2,4-dichlorophenyl)-5-(4-chlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide], on TSH, thyroxine (T(4)), and triiodothyronine (T(3)) secretions. Euthyroid male rats showed a 42% decrease in serum TSH, 2 h after a single i.p. injection of 0.02, but not 0.2 mg/kg body weight (BW), anandamide, accompanied by a 39% reduction in serum T(4), without alteration in serum T(3). At 0.5 and 1 h, these serum hormones showed no significant change. Hypothyroid rats showed a 35% reduction in serum TSH (P<0.01), 2 h after anandamide injection, which had no effect on hyperthyroid rats. In both thyroid states, no modification of serum thyroid hormones was observed. Intraperitoneal injection of 0.17 or 1.7 mg/kg BW AM251 in euthyroid rats caused, 1.5 h later, 1.7-fold or 4.3-fold increase in serum TSH respectively, without changing thyroid hormones. Stimulatory effect of 0.17 mg/kg BW AM251 and inhibitory effect of anandamide was abolished in the group injected with AM251 followed by an anandamide injection, 30 min later. Intracerebroventricular injection of 20 ng (but not 200 ng) anandamide induced a decrease in serum TSH at 60 min after injection, which tended to disappear at 120 min. Anterior pituitary explants presented significant reduction in TSH release in the presence of 10(-7) M anandamide in incubation medium, which was blocked by 10(-7) M AM251. In conclusion, anandamide has the ability to acutely inhibit TSH release in eu- and hypothyroid rats, acting at the hypothalamus-pituitary axis. Since, in addition, the cannabinoid receptor antagonist AM251 increased TSH release, we suggest that endocannabinoid system has a role as negative regulator of TSH secretion.

Effect of experimental hypo- and hyperthyroidism on serum adiponectin.

Adiponectin, an adipocyte-derived hormone, has been shown to decrease body weight by increasing thermogenesis and lipid oxidation. Thyroid hormones have similar effects. Here we investigated if experimental hypo- and hyperthyroidism in rats would induce changes in serum adiponectin concentration. Adult rats became hypothyroid by treatment with 0.03% methimazole in the drinking water for 28 days or hyperthyroid by subcutaneous thyroxine injections (50 microg/100g body weight) for 10 days. Serum adiponectin level of hyperthyroid rats was 3.2-fold higher than that of euthyroid ones (P < .001), whereas that in hypothyroid rats tended to be lower (38%), but without statistical significance. Serum adiponectin had a positive correlation with serum thyroxine (r = .81, P < .001) and triiodothyronine (r = 0.68, P = .03) and a negative correlation with serum thyroid-stimulating hormone (P = -.62, r = 0.015). In addition, there was a negative correlation between serum adiponectin level and total visceral white adipose mass (= sum of inguinal, epididymal, and retroperitoneal depots; r = -0.43; P = .032), which was reduced by 40.5% in hyperthyroid (P < .01) but not in hypothyroid animals. A positive association between serum adiponectin level and brown adipose tissue mass was found (r = 0.43, P = .03), but not with body weight, which was reduced in both hypo- and hyperthyroid groups. Adiponectin has been reported to have an insulin-sensitizing effect. However, in hyperthyroid rats, higher serum adiponectin level was not accompanied by statistically different changes in basal serum insulin levels, blood glucose concentrations, or glucose tolerance as compared with euthyroid rats, except for a slight increase in blood glucose level at 120 minutes after glucose intraperitoneal administration (P < .05). Therefore, experimental hypothyroidism did not change serum adiponectin concentration, whereas hyperthyroidism induced an important elevation in the serum hormone concentration, with still unknown biological significance.