Hypothalamic Content Research Articles

Physiologically relevant lactate accumulation from exercise or peripheral injection does not alter central or peripheral appetite signaling in mice

Lactate has been implicated in exercise-induced appetite suppression though little work has explored the mechanisms underpinning its role. Recent work suggests lactate accumulation via exercise and intracerebroventricular injection can alter central appetite regulating pathways, though a supraphysiological dose of lactate was administered centrally and there was no assessment of peripheral appetite markers. Therefore, we examined how physiologically relevant lactate accumulation via exercise or intraperitoneal injection altered central and peripheral appetite signaling pathways and whether the lactate dehydrogenase inhibitor oxamate could blunt any exercise effect. Forty 10-week-old C57BL/6 J male mice (n = 10/group) were assigned to either: 1) sedentary (SED + SAL; saline); 2) exercise (EX+SAL; saline); 3) exercise with oxamate (EX+OX; 750 mg‧kg−1 body mass); or 4) lactate (SED + LAC; 1.0 g‧kg−1 body mass). Blood, stomach, and hypothalamus samples were collected ∼2 h post-exercise/injection. Though oxamate blunted exercise-induced lactate accumulation compared to the EX+SAL condition (P = 0.044, d = 0.73), there were no differences in circulating acylated ghrelin or stomach ghrelin O-acyltransferase content between groups (P > 0.213, ηp2<0.125). There were also no differences in hypothalamic content for neuropeptide Y, proopiomelanocortin, agouti-related peptide, and alpha melanocyte-stimulating hormone (P > 0.150, ηp2<0.170). Exercise did increase phosphorylated-total signal transducer and activator of transcription 3 (pSTAT3) compared to EX+OX (p = 0.065, d = 1.23) but there were no differences in other markers of lactate signaling: phosphorylated-total adenosine monophosphate activated protein kinase, and protein kinase b (P > 0.121, ηp2<0.160). Our results suggest that lactate accumulation due to exercise or peripheral injection does not alter central or peripheral appetite signaling when measured 2 h post-exercise/injection, though pSTAT3 was blunted with oxamate.

Antipyretic effects of Xiangqin Jiere granules on febrile young rats revealed by combining pharmacodynamics, metabolomics, network pharmacology, molecular biology experiments and molecular docking strategies

Xiangqin Jiere granules (XQJRG) is a proprietary Chinese medicine treating children’s colds and fevers, but its mechanism of action is unclear. The aim of this study was to explore the antipyretic mechanisms of XQJRG based on pharmacodynamics, non-targeted metabolomics, network pharmacology, molecular biology experiments, molecular docking, and molecular dynamics (MD) simulation. Firstly, the yeast-induced fever model was constructed in young rats to study antipyretic effect of XQJRG. Metabolomics and network pharmacology studies were performed to identify the key compounds, targets and pathways involved in the antipyretic of XQJRG. Subsequently, MetScape was used to jointly analyze targets from network pharmacology and metabolites from metabolomics. Finally, the key targets were validated by enzyme-linked immunosorbent assay (ELISA), and the affinity and stability of key ingredient and targets were evaluated by molecular docking and MD simulation. The animal experimental results showed that after XQJRG treatment, body temperature of febrile rats was significantly reduced, 13 metabolites were significantly modulated, and pathways of differential metabolite enrichment were mainly related to amino acid and lipid metabolism. Network pharmacology results indicated that quercetin and kaempferol were the key active components of XQJRG, TNF, AKT1, IL6, IL1B and PTGS2 were core targets. ELISA confirmed that XQJRG significantly reduced the plasma concentrations of IL-1β, IL-6, and TNF-α, and the hypothalamic concentrations of COX-2 and PGE2. Molecular docking demonstrated that the binding energies of kaempferol to the core targets were all below −5.0 kcal/mol. MD simulation results showed that the binding free energies of TNF-kaempferol, IL6-kaempferol, IL1B-kaempferol and PTGS2-kaempferol were −87.86 kcal/mol, −70.41 kcal/mol, −69.95 kcal/mol and −106.67 kcal/mol, respectively. In conclusion, XQJRG has antipyretic effects on yeast-induced fever in young rats, and its antipyretic mechanisms may be related to the inhibition of peripheral pyrogenic cytokines release by constituents such as kaempferol, the reduction of hypothalamic fever mediator production, and the amelioration of disturbances in amino acid and lipid metabolism. Communicated by Ramaswamy H. Sarma

Supplementation with Jatobá-do-cerrado flour (Hymenaea stigonocarpa Mart.) decreases hypothalamic inflammation and improves obesity parameters in rats on a high-fat diet

To evaluate the impact of jatobá-do-cerrado flour on nutritional, inflammatory, and oxidative stress markers, an study was conducted using male Wistar rats. These animals were allocated into four groups: a standard diet (Control), a high-fat diet (HFD), a diet with jatobá-do-cerrado flour (JCF), and a combination of high-fat diet and jatobá-do-cerrado flour (HFD + JCF). Comprehensive evaluations included food intake, cytokine concentrations, and redox status indicators. HFD group exhibited increased caloric intake and fat mass, elevated circulating IL-6, and heightened lipid peroxidation markers. This group also showed increased hypothalamic concentrations of IL-6, TNFα, and lipid peroxidation. In contrast, the HFD + JCF group showed reduced caloric intake, fat mass, and improvements in redox balance and inflammatory markers both in the blood and hypothalamus. SummaryIn the current study, we evaluated the potential of Jatobá-do-cerrado flour in mitigating the effects of a high-fat diet in adult Wistar rats. The addition of fat to the animals' diet for 63 days induced obesity, dyslipidemia, as well as an increase in inflammatory and lipid peroxidation markers, both in the blood and hypothalamus. Conversely, supplementation with Jatobá-do-Cerrado flour showed anti-obesogenic effects and these may be associated with the reduction of inflammation and oxidative stress. Therefore, supplementation with this flour has the potential to be a functional food for the treatment or prevention of obesity.

Differential expressions of hypothalamic thermosensitive TRP ion channels may underlie the posthatching ontogeny of brain cooling capacity in broiler chickens

Two trials were performed to evaluate the association of hypothalamic abundances of thermosensitive transient receptor potential (TRP) ion channels with thermoregulation in broiler chickens. In trial 1, temporal changes in body temperatures, and hypothalamic expression patterns of TRP channels and thermoregulatory neurotransmitter concentrations were assessed from 3 to 42 d of age. In trial 2, the same variables were compared at 2 age stages between 2 distinct types of birds with high or low rectal temperatures (HRT or LRT). The core-to-brain temperature difference exhibited a rapid increase after hatching, arriving at a steady state in the fourth week (P < 0.01). The hypothalamus saw a progressive decrease of TRPV4 protein expression through 28 d (P < 0.01), followed by a great increase in the abundance of other channels right up to the end (P < 0.05). Compared to LRT birds, a decline in hypothalamic content of TRPV4 (P < 0.05), together with a bigger core-to-brain temperature difference (P < 0.01), was evident in the HRT counterpart at 33 d. In both trials, the core-to-brain and core-to-surface temperature differences were controlled in a synchronous and coordinated manner. These results allow concluding that developmental changes in the thermal sensitivity of hypothalamic neurons, determined by brain cooling capacity, involve a neuro-genomic mechanism, which regulates the ratio between thermosensitive TRP ion channels to attain a lower proportion of TRPV4 in comparison with other channels.

Leptin sensitizing effect of 1,3-butanediol and its potential mechanism

Leptin is an adipocyte-derived hormone that regulates appetite and energy expenditure via the hypothalamus. Since the majority of obese subjects are leptin resistant, leptin sensitizers, rather than leptin itself, are expected to be anti-obesity drugs. Endoplasmic reticulum (ER) stress in the hypothalamus plays a key role in the pathogenesis of leptin resistance. ATP-deficient cells are vulnerable to ER stress and ATP treatment protects cells against ER stress. Thus, we investigated the therapeutic effects of oral 1,3-butanediol (BD) administration, which increases plasma β-hydroxybutyrate and hypothalamic ATP concentrations, in diet induced obese (DIO) mice with leptin resistance. BD treatment effectively decreased food intake and body weight in DIO mice. In contrast, BD treatment had no effect in leptin deficient ob/ob mice. Co-administration experiment demonstrated that BD treatment sensitizes leptin action in both DIO and ob/ob mice. We also demonstrated that BD treatment attenuates ER stress and leptin resistance at the hypothalamus level. This is the first report to confirm the leptin sensitizing effect of BD treatment in leptin resistant DIO mice. The present study provides collateral evidence suggesting that the effect of BD treatment is mediated by the elevation of hypothalamic ATP concentration. Ketone bodies and hypothalamic ATP are the potential target for the treatment of obesity and its complications.

Metoprine, a histamine N-methyltransferase inhibitor, attenuates methamphetamine-induced hyperlocomotion via activation of histaminergic neurotransmission in mice

Metoprine increases the content of histamine in brain by inhibiting histamine N-methyltransferase (HMT), a centrally acting histamine degrading enzyme. We present data demonstrating that pretreatment with metoprine attenuates the hyperlocomotive effects of METH in mice using a multi-configuration behavior apparatus designed to monitor four behavioral outcomes [horizontal locomotion, appetitive behavior (food access), and food and water intake]. Metoprine pretreatment itself induced hyperlocomotion in mice challenged with saline during the large part of light phase. The trend was also observed during the following dark phase. This is the first report that metoprine has a long-lasting locomotor stimulating property. Similarly, in a tail suspension test, a single injection of metoprine significantly reduced total time of immobility in mice, consistent with the idea that metoprine possesses motor stimulating properties. Metoprine pretreatment did not affect other aspects of behavior. Metoprine did not affect the appetitive and drinking behavior while exerted an effect on stereotypy. No stereotyped behavior was observed in mice pretreated with vehicle followed by METH, while stereotyped sniffing was observed in mice pretreated with metoprine followed by METH. The metoprine pretreatment attenuated METH-induced hyperlocomotion during the first 2 h of light phase, suggesting that metoprine-induced locomotor stimulating property might be different from that of METH. The hypothalamic content of histamine (but not its brain metabolite) was increased after metoprine or METH administration. Both METH and metoprine reduced dopamine and histamine turnover in the striatum and the nucleus accumbens and the hypothalamus, respectively, and there is a significant metoprine pretreatment x METH challenge interaction in the histamine turnover. It is likely that metoprine may attenuate METH-induced hyperlocomotion via activation of histaminergic neurotransmission. Metoprine also might induce a long-lasting locomotor stimulating effect via a putative mechanism different from that whereby METH induces the locomotor stimulating effect.

Fructose-rich diet and walnut supplementation differently regulate rat hypothalamic and hippocampal glucose transporters expression.

Nutritional modulations may be considered a strategy to protect mental health. Neuronal homeostasis is highly dependent on the availability of glucose, which represents the primary energy source for the brain. In this study, we evaluated the effects of walnut intake and fructose-rich diet on the expression of glucose transporters (GLUTs) in two rat brain regions: hypothalamus and hippocampus. Our results show that walnut supplementation of fructose-fed animals restored the hypothalamic content of GLUT1 and GLUT3 protein. Furthermore, walnut intake did not affect increased hypothalamic GLUT2 content upon fructose consumption. These effects were accompanied by distinctive alterations of hippocampal GLUTs levels. Specifically, walnut intake increased GLUT1 content, whereas GLUT2 protein was decreased within the rat hippocampus after both individual and combined treatments. Overall, our study suggests that walnut supplementation exerted modulatory effects on the glucose transporters within specific brain regions in the presence of developed metabolic disorder. © 2021 Society of Chemical Industry.

Different response of hypothalamus and temporal cortex to intranasal insulin in rat model of sporadic Alzheimer's disease

AbstractBackgroundSporadic Alzheimer’s disease (sAD) is the most common form of dementia. Central administration of streptozotocin (STZ‐icv) has been shown to induce Alzheimer‐like changes and has been proposed as a non‐transgenic sAD animal model. Intranasal insulin administration is being investigated as a possible pharmacological treatment in order to reverse and ameliorate brain insulin dysfunction, but exact mechanism is not yet clear.MethodMale Wistar rats were given icv vehicle or STZ (3 mg/kg). Activation of c‐fos co‐localized with neuronal, astrocytic and microglial markers was evaluated in the brain 2 hours after intranasal insulin administration (2 IU), which was given 1 month after STZ. Western blot analysis of insulin receptor (IR) and postsynaptic marker (PSD95) were performed in hypothalamus (HPT) and temporal cortex (TC) 2h after intranasal insulin administration in STZ‐icv rat model. Spectrophotometry was used to measure glucose and β‐amyloid in plasma and CSF and glutamate and insulin concentration in brain tissue samples.ResultIntranasal insulin significantly increases c‐fos expression in TC only. C‐fos expression in TC was co‐localized with neuron marker, while in HPT was co‐localized also with microglial marker, especially with activated microglia in STZ‐icv rats. Glucose levels were found unaltered in plasma and CSF, while β‐amyloid concentration was found slightly increased after STZ and insulin administration. Increment of insulin concentration was found most pronounced in HPT of control animals after intranasal insulin (+289% vs CTR). Both insulin and STZ significantly decreases glutamate concentration in HPT (∼−92% vs CTR). treatments mostly s. At the level of IR and PSD95 expression STZ and insulin have opposite effects in HPT compared to TC.ConclusionIn this research, we have shown that STZ and insulin have different and opposite effects in the brain, showing distinct cell response to insulin depending on brain region in rat model of sAD. Financed by CSF projects IP‐09‐2014‐4639 and IP‐01‐2018‐8938. This publication was co‐financed by the Scientific Centre of Excellence for Basic, Clinical and Translational Neuroscience (project “Experimental and clinical research of hypoxic‐ischemic damage in perinatal and adult brain”; GA KK01.1.1.01.0007 funded by the European Union through the European Regional Development Fund).

Short-term fasting differentially regulates PI3K/AkT/mTOR and ERK signalling in the rat hypothalamus

It is known that insulin secreted by pancreatic β-cells enters the brain by crossing the blood–brain barrier. However, it was demonstrated that insulin expression occurs in various brain regions as well. Albeit the list of insulin actions in the brain is long and it includes control of energy homeostasis, neuronal survival, maintenance of synaptic plasticity and cognition, not much is known about the adaptive significance of insulin synthesis in brain.We previously reported that short-term fasting promotes insulin expression and subsequent activation of insulin receptor in the rat periventricular nucleus. In order to uncover a physiological importance of the fasting-induced insulin expression in hypothalamus, we analyzed the effect of short-term food deprivation on the expression of several participants of PI3K/AKT/mTOR and Ras/MAPK signaling pathways that are typically activated by this hormone.We found that the hypothalamic content of total and activated IRS1, IRS2, PI3K, and mTOR remained unchanged, but phosphorylated AKT1/2/3 was decreased. The levels of activated ERK1/2 were increased after six-hour fasting. Moreover, activated ERK1/2 was co-expressed with activated insulin receptor in the nucleus arcuatus. Our previously published and current findings suggest that the ERK activation in hypothalamus was at least partially initiated by the centrally produced insulin.

1771-P: Hypothalamic Perineuronal Net Assembly Is Required for Sustained Diabetes Remission Induced by FGF1

Defective glucoregulatory neurocircuit activity within the hypothalamic arcuate nucleus (ARC) is implicated in the pathogenesis of type 2 diabetes (T2D). In the ARC of T2D-Zucker Diabetic Fatty (ZDF) rats, we have identified significant changes in the composition and abundance of extracellular perineuronal nets (PNNs) that enmesh glucoregulatory neurocircuits. Imaging of ARC PNNs, which are comprised of the chondroitin sulfate (CS) proteoglycan aggrecan and attached CS glycosaminoglycans (GAGs), show that T2D-ZDF rats exhibit a 66.4% and 77.3% decrease in aggrecan in the medial and lateral ARC areas, respectively, compared to normoglycemic controls. Distinctive sulfation of the attached CS-GAG isomers (0S-, 4S-, 6S-, 4S6S-, 2S6S-CS) differentially influence the function of PNNs. Using LC-MS/MS, we provide the first description of hypothalamic CS-GAG sulfation patterns and show that in T2D-ZDF rats, levels of the ∆4S- isomer is increased, whereas ∆6S- and ∆2S6S-CS isomers are decreased, differences predicted to disrupt protein-GAG interactions involved in neurite outgrowth and favor tissue stiffening. To determine if ARC PNNs are targets for the antidiabetic effect of fibroblast growth factor 1 (FGF1), we performed intracerebroventricular (icv) injection of FGF1 in ZDF rats and report that both the hypothalamic CS-GAG sulfation patterns and content of ARC PNNs are normalized 24 d after treatment. Western blot analysis shows that the latter effect entails a 1.7-fold increase in aggrecan protein abundance. To assess the functional significance of ARC PNN restoration by FGF1, ZDF rats received an icv FGF1 injection followed by bilateral microinjection of either ChABC, a PNN digesting enzyme, or its vehicle control into the ARC. Our finding that the duration of sustained FGF1-induced blood glucose lowering was shortened following ARC PNN digestion (p&amp;lt;0.05) identifies PNNs as novel participants in the central control of glucose homeostasis and diabetes remission by FGF1. Disclosure K.M. Alonge: Research Support; Self; Novo Nordisk Inc. Z. Mirzadeh: None. J. Scarlett: None. A. Logsdon: None. J.M. Brown: None. E. Cabrales: None. C.K. Chan: None. K. Kaiyala: None. M.A. Bentsen: None. W.A. Banks: None. M. Guttman: None. T.N. Wight: None. G.J. Morton: Research Support; Self; Novo Nordisk A/S. M.W. Schwartz: Research Support; Self; Novo Nordisk A/S. Funding National Institutes of Health (P30DK017047, F32DK122662, R01DK101997, R01DK089056, R01DK083042, K08DK114474, R01GM127579, K12NS080223, P30DK035816); Barrow Neurological Foundation (1800253005); University of Washington; Novo Nordisk (CMS431104); Novo Nordisk Foundation (NNF170C0024328, NNF10CC1016515)

Fetal betaine exposure modulates hypothalamic expression of cholesterol metabolic genes in offspring cockerels with modification of promoter DNA methylation

In documents, maternal betaine modulates hypothalamic cholesterol metabolism in chicken posthatchings, but it remains unclear whether this effect can be passed on by generations. In present study, eggs were injected with saline or betaine at 2.5 mg/egg, and the hatchlings (F1) were raised under the same condition until sexual maturation. Both the control group and the betaine group used artificial insemination to collect sperm from their cockerels. Fertilized eggs were incubated, and the hatchlings of the following generation (F2) were raised up to 64 D of age. F2 cockerels in betaine group showed significantly (P < 0.05) lower body weight, which was associated with significantly decreased (P < 0.05) hypothalamic content of total cholesterol and cholesterol ester. Concordantly, hypothalamic expression of cholesterol biosynthetic genes, SREBP2 and HMGCR, were significantly downregulated (P < 0.05), together with cholesterol conversion-related and excretion-related genes, CYP46A1 and ABCA1. These changes coincided with a significant downregulation in mRNA expression of regulatory neuropeptides including brain-derived neurotrophic factor, neuropeptide Y, and corticotropin-releasing hormone. Moreover, genes involved in methyl transfer cycle were also modified. Betaine homocysteine methyltransferase (P < 0.05) was downregulated, yet DNA methyltransferase1 tended to be upregulated (P = 0.06). S-adenosyl methionine/S-adenosylhomocysteine ratio was higher in the hypothalamus of betaine-treated F2 cockerels, which was associated with significantly modified CpG methylation on the promoter of those affected genes. These results suggested that betaine might regulate central cholesterol metabolism and hypothalamic expression of genes related to brain function by altering promoter DNA methylation in F2 cockerels.

Adrenalectomy impairs insulin-induced hypophagia and related hypothalamic changes

Adrenalectomy (ADX) induces hypophagia and glucocorticoids counter-regulate the peripheral metabolic effects of insulin. This study evaluated the effects of ADX on ICV (lateral ventricle) injection of insulin-induced changes on food intake, mRNA expression of hypothalamic neuropeptides (insulin receptor (InsR), proopiomelanocortin, cocaine and amphetamine-regulated transcript (Cart), agouti-related protein, neuropeptide Y (Npy) in the arcuate nucleus of the hypothalamus (ARC), corticotrophin-releasing factor in the paraventricular nucleus of the hypothalamus) and hypothalamic protein content of insulin signaling-related molecules (insulin receptor substrate (IRS) 1, protein kinase B (AKT), extracellular-signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), protein tyrosine phosphatase-1B (PTP1B) and T cell protein tyrosine phosphatase (TCPTP)) Compared with sham animals, ADX increased the hypothalamic content of pJNK/JNK, PTP1B and TCPTP, as well as decreased mRNA expression of InsR, and corticosterone (B) treatment reversed these effects. Insulin central injection enhanced hypothalamic content of pAKT/AKT and Cart mRNA expression, decreased Npy mRNA expression and food intake only in sham rats, without effects in ADX and ADX + B rats. Insulin did not alter the hypothalamic phosphorylation of IRS1 and ERK1/2 in the three experimental groups. These data demonstrate that ADX reduces the expression of InsR and increases insulin counter-regulators in the hypothalamus, as well as ADX abolishes hypophagia, activation of hypothalamic AKT pathway and changes in Cart and Npy mRNA expression in the ARC induced by insulin. Thus, the higher levels of insulin counter-regulatory proteins and lower expression of InsR in the hypothalamus are likely to underlie impaired insulin-induced hypophagia and responses in the hypothalamus after ADX.

Hypothalamic concentrations of kisspeptin and gonadotropin‐releasing hormone during the breeding season and non‐breeding season in ewes

Current methods to quantify kisspeptin (KP) are limited. To this end, a radioimmunoassay (RIA) specific for KP was developed and validated. We hypothesized that use of a RIA would reveal multiple hypothalamic regions as targets of negative seasonal feedback of estradiol on KP production in sheep. Ovariectomized (OVX) ewes bearing a subcutaneous implant of estradiol were euthanized during the breeding season (BS) (n=4) and non-breeding season (NBS) (n=3). Coronal sections of preoptic area (POA), anterior hypothalamic area (AHA), and mediobasal hypothalamus (MBH) were collected, as well as the median eminence (ME), cortex, brain stem, and cerebellum. Amounts of KP and gonadotropin-releasing hormone (GnRH) in individual hypothalamic nuclei were quantified by radioimmunoassay. Concentration and content of KP were lower during the NBS than the BS in the MBH (P<0.01) and POA (P<0.01). Levels of KP in tissue adjacent to the POA and MBH were much lower, and neither concentration nor content of KP differed between the BS and NBS. Kisspeptin was also detected in the cortex, brain stem, and cerebellum, but concentrations were not affected by season. In addition, concentration and content of GnRH in the POA, AHA, MBH, and ME were similar between seasons. Our RIA results indicate that in addition to the MBH, the POA and AHA appear to be involved in the seasonal negative feedback of estradiol on KP expression.

Hypothalamic Glucose Concentrations Are Higher in Subjects with Type 1 Diabetes (T1D) and Impaired Awareness of Glycemia (IAH) than in T1D without IAH

IAH occurs commonly in patients with T1D but its pathogenesis remains uncertain. Previous investigation has suggested that recurrent hypoglycemia leads to an upregulation of brain glucose transport thereby assuring that the brain will have better fuel delivery during subsequent episodes of hypoglycemia. If so, subjects with T1D and IAH should have higher hypothalamic brain glucose concentrations than subjects with T1D without IHA when studied at the same level of glycemia. Here we used 1H-magnetic resonance spectroscopy at 7 T to measure (Glucose+Taurine)/ total Creatine in a 13x12x10 mm3 hypothalamic voxel in such patient groups while they were maintained at euglycemia and then hypoglycemia using a glucose clamp. Since taurine and creatine do not change with glycemia, this is a valid measure of brain glucose concentrations. IAH was defined using the Clarke questionnaire with subjects found indeterminate further classified using the Gold questionnaire. We found that hypothalamic (Glucose+Taurine)/ total Creatine was significantly higher in T1D with IAH at both euglycemia and hypoglycemia when compared to T1D without IAH. These data support the hypothesis that a change in glucose transport may contribute to the pathogenesis of IAH. T1D with IAH (n=9)T1D without IAH (n=9)Age (years)47.6 ± 1729.2 ± 8Hemoglobin A1c (%)7.3 ± 0.97.3 ± 0.7Glycemia at euglycemia (mg/dl)98 ± 495 ± 7Glycemia during hypoglycemia (mg/dl)48 ± 348 ± 5Epinephrine during hypoglycemia (pg/ml)250 ± 155711±442*Symptom score during hypoglycemia8 ± 936 ± 14**Hypothalamic glucose at euglycemia (Glucose+Taurine)/ total Creatine (mM)0.43 ± 0.110.27 ± 0.08**Hypothalamic glucose at hypoglycemia (Glucose+Taurine)/ total Creatine (mM)0.23 ± 0.040.15 ± 0.02***p=0.03, **p &amp;lt; 0.001. Disclosure A. Moheet: None. D. Deelchand: None. A. Kumar: None. G. Oz: Research Support; Self; Takeda Pharmaceuticals U.S.A., Inc. E.R. Seaquist: Advisory Panel; Self; Eli Lilly and Company. Consultant; Self; Eli Lilly and Company, Sanofi, Zucera, InfoMed, 360 consulting. Other Relationship; Self; Novo Nordisk Inc..

Possible Obesogenic Effects of Bisphenols Accumulation in the Human Brain

Evidence of bisphenols’ obesogenic effects on humans is mixed and inconsistent. We aimed to explore the presence of bisphenol A (BPA), bisphenol F (BPF) and chlorinated BPA (ClBPA), collectively called the bisphenols, in different brain regions and their association with obesity using post-mortem hypothalamic and white matter brain material from twelve pairs of obese (body mass index (BMI) >30 kg/m2) and normal-weight individuals (BMI <25 kg/m2). Mean ratios of hypothalamus:white matter for BPA, BPF and ClBPA were 1.5, 0.92, 0.95, respectively, suggesting no preferential accumulation of the bisphenols in the grey matter (hypothalamic) or white matter-enriched brain areas. We observed differences in hypothalamic concentrations among the bisphenols, with highest median level detected for ClBPA (median: 2.4 ng/g), followed by BPF (2.2 ng/g) and BPA (1.2 ng/g); similar ranking was observed for the white matter samples (median for: ClBPA-2.5 ng/g, BPF-2.3 ng/g, and BPA-1.0 ng/g). Furthermore, all bisphenol concentrations, except for white-matter BPF were associated with obesity (p < 0.05). This is the first study reporting the presence of bisphenols in two distinct regions of the human brain. Bisphenols accumulation in the white matter-enriched brain tissue could signify that they are able to cross the blood-brain barrier.

Dietary betaine supplementation in hens modulates hypothalamic expression of cholesterol metabolic genes in F1 cockerels through modification of DNA methylation.

Betaine is widely used in animal nutrition to promote growth, development and methyl donor during methionine metabolism through nutritional reprogramming via regulation of gene expression. Prenatal betaine exposure is reported to modulate hypothalamic cholesterol metabolism in chickens, yet it remains unknown whether feeding hens with betaine-supplemented diet may affect hypothalamic cholesterol metabolism in F1 offspring. In this study, hens were fed with basal or betaine-supplemented (0.5%) for 30days, and the eggs were collected for incubation. The hatchlings were raised under the same condition up to 56days of age. Betaine-treated group showed significantly (P<0.05) higher plasma concentration of total cholesterol and HDL-cholesterol, together with increased hypothalamic content of total cholesterol and cholesterol ester. Concordantly, hypothalamic gene expression of SREBP2, HMGCR, and LDLR was significantly up regulated (P<0.05). Also, mRNA abundances of SREBP1, ACAT1 and APO-A1 were up-regulated, while that of CYP46A1 was significantly down-regulated (P<0.05). These changes coincided with a significant down-regulation of BDNF and CRH, and a significant up-regulation of NPY mRNA expression. Moreover, genes involved in methyl transfer cycle were also modulated. DNMT1 and BHMT were up-regulated (P<0.05) at both mRNA and protein levels, which was associated with significant modifications of CpG methylation on the promoter of SREBP-1, SREBP-2 and APO-A1 genes as detected by bisulfate sequencing. These results indicate that feeding betaine to hens modulates hypothalamic expression of genes involved in cholesterol metabolism and brain functions in F1 cockerels with modification of promoter DNA methylation.

Crosstalks between kisspeptin neurons and somatostatin neurons are not photoperiod dependent in the ewe hypothalamus

Seasonal reproduction is under the control of gonadal steroid feedback, itself synchronized by day-length or photoperiod. As steroid action on GnRH neurons is mostly indirect and therefore exerted through interneurons, we looked for neuroanatomical interactions between kisspeptin (KP) neurons and somatostatin (SOM) neurons, two populations targeted by sex steroids, in three diencephalic areas involved in the central control of ovulation and/or sexual behavior: the arcuate nucleus (ARC), the preoptic area (POA) and the ventrolateral part of the ventromedial hypothalamus (VMHvl). KP is the most potent secretagogue of GnRH secretion while SOM has been shown to centrally inhibit LH pulsatile release. Notably, hypothalamic contents of these two neuropeptides vary with photoperiod in specific seasonal species. Our hypothesis is that SOM inhibits KP neuron activity and therefore indirectly modulate GnRH release and that this effect may be seasonally regulated. We used sections from ovariectomized estradiol-replaced ewes killed after photoperiodic treatment mimicking breeding or anestrus season. We performed triple immunofluorescent labeling to simultaneously detect KP, SOM and synapsin, a marker for synaptic vesicles. Sections from the POA and from the mediobasal hypothalamus were examined using a confocal microscope. Randomly selected KP or SOM neurons were observed in the POA and ARC. SOM neurons were also observed in the VMHvl. In both the ARC and POA, nearly all KP neurons presented numerous SOM contacts. SOM neurons presented KP terminals more frequently in the ARC than in the POA and VMHvl. Quantitative analysis failed to demonstrate major seasonal variations of KP and SOM interactions. Our data suggest a possible inhibitory action of SOM on all KP neurons in both photoperiodic statuses. On the other hand, the physiological significance of KP modulation of SOM neuron activity and vice versa remain to be determined.

Effects of ghrelin agonist and antagonist on endogenous desacyl-ghrelin content in the brain limbical structures under psychoemotional stress in rats

Background. During last years it has been shown the ghrelin signaling system not only regulates energy balance and food intake. It also takes part in reinforcement mechanisms and addiction formation. So the ghrelin system may be considered as possible molecular target to study addiction treatment and post-stressor pharmacological modulation.&#x0D; The aim of this work was to study the effects of ghrelin agonist and antagonist administration on des-acyl ghrelin (DAG) content in the brain structures under stress exposure in Wistar rats.&#x0D; Methods. The acute psychoemotional stress was realized by means of exposure of experimental rats to predator, a tiger python. Ghrelin or ghrelin antagonist D-Lys3-GHRP-6 (Tocris, UK) 10 µg in 20 µl administered intranasally for 7 days after stress exposure. Then brain structures were obtained, homogenized with cryogenic system “Cryomill 200” (Retsch, Germany) and investigated with high-sensitive ELISA (SP-BIO, France). Results. DAG have been detected in every brain structures studied. That are amygdala, hippocampus and hypothalamus. In control group of animals the DAG concentration in hypothalamus was 3-fold more comparning to hippocampus and 2-fold more conparning to amygdala content. The acute stress have dramatically 8-12-fold decrease of DAG concentrations in every brain structures studied. The pharmacological actions on GHSR receptor by ghrelin agonist and antagonist have not affect significant changes in DAG concentrations in every brain structures.&#x0D; Conclusions. The different concentrations of DAG in brain structures in control gtoup supports the view about ghrelin releasing neurons in the hypothalamus. Intranasal administration of ghrelin agonist and antagonist changes the levels of DAG in the hippocampus and the hypothalamus but not in the amygdala nucleus. Our data confirm the opinion about ghrelin-releasing neurons in hypothalamus. The experiments showed the acute stress had caused great depression of ghrelin system in various brain structures. The response of ghrelin system to acute stress occur possibly besides GHSR receptor pathway. The last have been suggested by absence of significant response to ghrelin agonist and antagonist administration.

Participation of hypothalamic CB1 receptors in reproductive axis disruption during immune challenge.

Immune challenge inhibits reproductive function and endocannabinoids (eCB) modulate sexual hormones. However, no studies have been performed to assess whether the eCB system mediates the inhibition of hormones that control reproduction as a result of immune system activation during systemic infections. For that reason, we evaluated the participation of the hypothalamic cannabinoid receptor CB1 on the hypothalamic-pituitary-gonadal (HPG) axis activity in rats submitted to immune challenge. Male adult rats were treated i.c.v. administration with a CB1 antagonist/inverse agonist (AM251) (500ng/5 μL), followed by an i.p. injection of lipopolysaccharide (LPS) (5mg/kg) 15minutes later. Plasmatic, hypothalamic and adenohypophyseal pro-inflammatory cytokines, hormones and neuropeptides were assessed 90 or 180minutes post-LPS. The plasma concentration of tumour necrosis factor α and adenohypophyseal mRNA expression of Tnfα and Il1β increased 90 and 180minutes post i.p. administration of LPS. However, cytokine mRNA expression in the hypothalamus increased only 180minutes post-LPS, suggesting an inflammatory delay in this organ. CB1 receptor blockade with AM251 increased LPS inflammatory effects, particularly in the hypothalamus. LPS also inhibited the HPG axis by decreasing gonadotrophin-releasing hormone hypothalamic content and plasma levels of luteinising hormone and testosterone. These disruptor effects were accompanied by decreased hypothalamic Kiss1 mRNA expression and prostaglandin E2 content, as well as by increased gonadotrophin-inhibitory hormone (Rfrp3) mRNA expression. All these disruptive effects were prevented by the presence of AM251. In summary, our results suggest that, in male rats, eCB mediate immune challenge-inhibitory effects on reproductive axis at least partially via hypothalamic CB1 activation. In addition, this receptor also participates in homeostasis recovery by modulating the inflammatory process taking place after LPS administration.

Anxiety-like behavioural effects of extremely low-frequency electromagnetic field in rats

In recent years, extremely low-frequency electromagnetic field (ELF-EMF) has received considerable attention for its potential biological effects. Numerous studies have shown the role of ELF-EMF in behaviour modulation. The aim of this study was to investigate the effect of short-term ELF-EMF (50Hz) in the development of anxiety-like behaviour in rats through change hypothalamic oxidative stress and NO. Ten adult male rats (Wistar albino) were divided in two groups: control group-without exposure to ELF-EMF and experimental group-exposed to ELF-EMF during 7days. After the exposure, time open field test and elevated plus maze were used to evaluate the anxiety-like behaviour of rats. Upon completion of the behavioural tests, concentrations of superoxide anion (O2·-), nitrite (NO2-, as an indicator of NO) and peroxynitrite (ONOO-) were determined in the hypothalamus of the animals. Obtained results show that ELF-EMF both induces anxiety-like behaviour and increases concentrations of O2·- and NO, whereas it did not effect on ONOO- concentration in hypothalamus of rats. In conclusion, the development of anxiety-like behaviour is mediated by oxidative stress and increased NO concentration in hypothalamus of rats exposed to ELF-EMF during 7days.