leptin and glyceryl-2-arachidonate

The present study summarized recent findings on roles of leptin and endocannabinoids as modulators of the peripheral components of sweet taste. The positive effect of endocannabinoids on sweet sensitivity was opposed to that of leptin which suppresses sweet sensitivity. Leptin and endocannabinoids, therefore, not only regulate food intake via central nervous systems but also may modulate palatability of foods by altering peripheral sweet taste responses via their cognate receptors. Orexigenic and anorexigenic factors such as endocannnabinoids and leptin may affect energy homeostasis by regulating taste sensitivity.

Topics: Animals; Arachidonic Acids; Cannabinoid Receptor Modulators; Carbohydrates; Circadian Rhythm; Eating; Endocannabinoids; Energy Metabolism; Glycerides; Humans; Insulin; Leptin; Mice; Receptor, Cannabinoid, CB1; Receptors, G-Protein-Coupled; Sucrose; Taste; Taste Buds

The endocannabinoid (eCB) system partly controls hedonic eating, a major cause of obesity. While some studies suggested an overactivation of the eCB system in obesity, peripheral levels of eCBs across the 24-hour cycle have not been characterized in obese individuals despite the fact that in lean adults, levels of the eCB 2-arachidonoylglycerol (2-AG) vary across the day.. We sought to examine 24-hour profiles of serum concentrations of 2-AG in healthy obese and nonobese adults, under well-controlled laboratory conditions. We also simultaneously assessed 24-hour profiles of 2-oleoylglycerol (2-OG), leptin, and cortisol in each participant.. With fixed light-dark and sleep-wake cycles, blood sampling was performed over an entire 24-hour period, including identical meals at 0900, 1400, and 1900.. Twelve obese (8 women, mean body mass index [BMI]: 39.1 kg/m2) and 15 nonobese (6 women; mean BMI: 23.6 kg/m2) healthy adults were studied.. We observed a 24-hour variation of 2-AG levels in obese individuals but, relative to nonobese adults, the amplitude was dampened and the timings of the nadir and peak were delayed by 4 to 5 hours. The profile of 2-OG was similarly misaligned. In contrast, when expressed relative to the 24-hour mean level, the 24-hour rhythm of cortisol and leptin were similar in obese and nonobese participants.. Obesity appears to be associated with a dampening and delay of the 24-hour variation of eCB activity relative to the central circadian signal as well as to the daily leptin rhythm. This misalignment may play a role in the pathophysiology of obesity.

Topics: Adult; Arachidonic Acids; Case-Control Studies; Circadian Rhythm; Endocannabinoids; Female; Glycerides; Humans; Hydrocortisone; Leptin; Male; Obesity; Young Adult

Binge eating disorder (BED) is known as the most common eating disorder with both psychosocial and biological factors involved. In this regard, there is a need to recognize probable disturbances in substances involved in food intake regulation in BED. In this study, we hypothesized that the levels of endocannabinoids, fatty acid amid hydrolase (FAAH) gene polymorphisms, and appetite regulatory substances are different in overweight and obese women with and without BED. A Binge Eating Scale was used to estimate the prevalence of BED in 180 women classified as overweight or obese. The levels of anandamide (AEA), 2-arachidonoylglycerol (2-AG), leptin, insulin, and orexin-A were measured by enzyme-linked immunosorbent assay kits. The subjects were genotyped for polymorphisms of FAAH gene using amplification refractory mutation system-polymerase chain reaction. Data were analyzed using SPSS software. About 41.6% (n = 75) of the subjects were diagnosed with BED. Women with BED exhibited significantly higher levels of AEA, 2-AG, leptin, and insulin compared to non-BED women (P < .05). Binary logistic regression analysis also showed that AEA, leptin, and insulin were the predictors of having BED after adjusting for body mass index (P < .05). In addition, the frequency of A allele of FAAH gene was higher in women with BED compared to women without BED; however, there were no significant differences between these 2 groups (P = .08). These results supported our hypothesis in the cases of AEA, 2-AG, leptin, and insulin but not orexin and FAAH gene polymorphisms. The findings of the current study provide further evidence concerning the role of these substances in BED.

Topics: Adult; Amidohydrolases; Arachidonic Acids; Binge-Eating Disorder; Body Mass Index; Cross-Sectional Studies; Endocannabinoids; Female; Genotype; Glycerides; Humans; Insulin; Leptin; Obesity; Orexins; Overweight; Polymorphism, Genetic; Polyunsaturated Alkamides

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Topics: Animals; Arachidonic Acids; Cannabinoid Receptor Agonists; Endocannabinoids; Glycerides; Leptin; Mice; Mice, Obese; Neurons; Orexins; Synaptic Potentials

Pain perception can become altered in individuals with eating disorders and obesity for reasons that have not been fully elucidated. We show that leptin deficiency in ob/ob mice, or leptin insensitivity in the arcuate nucleus of the hypothalamus in mice with high-fat diet (HFD)-induced obesity, are accompanied by elevated orexin-A (OX-A) levels and orexin receptor-1 (OX1-R)-dependent elevation of the levels of the endocannabinoid, 2-arachidonoylglycerol (2-AG), in the ventrolateral periaqueductal gray (vlPAG). In ob/ob mice, these alterations result in the following: (i) increased excitability of OX1-R-expressing vlPAG output neurons and subsequent increased OFF and decreased ON cell activity in the rostral ventromedial medulla, as assessed by patch clamp and in vivo electrophysiology; and (ii) analgesia, in both healthy and neuropathic mice. In HFD mice, instead, analgesia is only unmasked following leptin receptor antagonism. We propose that OX-A/endocannabinoid cross talk in the descending antinociceptive pathway might partly underlie increased pain thresholds in conditions associated with impaired leptin signaling.

Topics: Animals; Arachidonic Acids; Disease Models, Animal; Endocannabinoids; Glycerides; Leptin; Male; Membrane Potentials; Mice, Obese; Neural Pathways; Neurons; Nociceptive Pain; Orexin Receptors; Orexins; Pain Perception; Periaqueductal Gray; Tissue Culture Techniques

In recent years, endocannabinoids emerged as new players in various reproductive events. Recently, we demonstrated the involvement of 2-arachidonoylglycerol (2-AG) in human cytotrophoblast apoptosis and syncytialization. However, 2-AG impact in hormone production by the syncytiotrophoblast (hST) was never studied. In this work, we demonstrate that 2-AG activates cannabinoid (CB) receptors, exerting an inhibitory action on cyclic AMP/protein kinase A (cAMP/PKA) and mitogen-activated protein kinase (MAPK) p38 pathways, and enhancing ERK 1/2 phosphorylation. Furthermore, 2-AG affects the synthesis of human chorionic gonadotropin (hCG), leptin, aromatase, 3-β-hydroxysteroid dehydrogenase (3-β-HSD), and placental protein 13 (PP13). These 2-AG effects are mediated by the activation of CB receptors, in a mechanism that may involve p38, ERK 1/2 and cAMP/PKA pathways, which participate in the regulation of placental proteins expression. To our knowledge, this is the first study that associates the endocannabinoid signalling and endocrine placental function, shedding light on a role for 2-AG in the complex network of molecules that orchestrate the production of placental proteins essential for the gestational success.

Topics: 3-Hydroxysteroid Dehydrogenases; Arachidonic Acids; Aromatase; Cannabinoid Receptor Agonists; Cells, Cultured; Chorionic Gonadotropin; Cyclic AMP-Dependent Protein Kinases; Dose-Response Relationship, Drug; Endocannabinoids; Extracellular Signal-Regulated MAP Kinases; Female; Galectins; Glycerides; Humans; Leptin; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Pregnancy; Pregnancy Proteins; Protein Biosynthesis; Signal Transduction; Time Factors; Trophoblasts

A balanced cytotrophoblast cell turnover is crucial for placental development and anomalies in this process associated with gestational diseases. The endocannabinoid system (ECS) has emerged as a new player in several biological processes. However, its influence during placental development is still unknown. We report here the expression of the endocannabinoid 2-arachidonoylglycerol (2-AG) main metabolic enzymes in human cytotrophoblasts and syncytiotrophoblast. We also showed that 2-AG induced a decrease in placental alkaline phosphatase activity, human chorionic gonadotropin secretion and Leptin mRNA levels. Moreover, 2-AG reduced glial cell missing 1 and syncytin-2 transcription and the number of nuclei in syncytium. These effects were mediated by cannabinoid receptors and may result from 2-AG inhibition of the cAMP/PKA signalling pathway. Our data suggest that 2-AG may interfere with the biochemical and morphological differentiation of human cytotrophoblasts, through a CB receptor-dependent mechanism, shedding light on a role for the ECS in placental development.

Topics: Adult; Alkaline Phosphatase; Arachidonic Acids; Chorionic Gonadotropin; Cyclic AMP-Dependent Protein Kinases; Endocannabinoids; Female; Giant Cells; Glycerides; Humans; Leptin; Pregnancy; Pregnancy Proteins; Signal Transduction; Trophoblasts

The endocannabinoid (eCB) system is involved in the regulation of food intake and of peripheral metabolism. Although the cross talk between energy metabolism and the circadian system is well documented, little is known about a potential circadian modulation of human eCB activity.. The objective of the study was to define the 24-hour profile of circulating levels of the most abundant endogenous ligand of the CB1 receptor, 2-arachidonoylglycerol (2-AG), in healthy young nonobese adults studied under controlled bedtime, dietary, and activity conditions.. Fourteen subjects participated in this 4-day laboratory study with fixed light-dark cycles, standardized meals, and bedtimes. Sleep was recorded each night. On the third day, blood sampling at 15- to 30-minute intervals began at 9:30 pm and continued for 24 hours. Cortisol, leptin, and ghrelin were assayed on all samples, whereas the levels of 2-AG and its structural analog, 2-oleoylglycerol (2-OG), were measured at 60-minute intervals.. All participants exhibited a large circadian variation of 2-AG serum concentrations with a nadir around midsleep, coincident with the middle of the overnight fast. Levels of 2-AG increased continually across the morning, peaking in the early to midafternoon. Peak values represented, on average, a nearly 3-fold increase above nocturnal nadir levels. Concentrations of 2-OG followed a similar pattern, although with a shorter morning increase and lower amplitude.. The findings demonstrate that activity of the eCB system is profoundly modulated by circadian rhythmicity and suggest that its impact on the regulation of food intake is suppressed during sleep and is maximal during early to midafternoon.

Topics: Adolescent; Adult; Arachidonic Acids; Circadian Rhythm; Eating; Endocannabinoids; Female; Ghrelin; Glycerides; Humans; Hydrocortisone; Leptin; Male; Sleep; Young Adult

Potential roles of endogenous leptin and endocannabinoids in sweet taste were examined by using pharmacological antagonists and mouse models including leptin receptor deficient (db/db) and diet-induced obese (DIO) mice. Chorda tympani (CT) nerve responses of lean mice to sweet compounds were increased after administration of leptin antagonist (LA) but not affected by administration of cannabinoid receptor antagonist (AM251). db/db mice showed clear suppression of CT responses to sweet compounds after AM251, increased endocannabinoid levels in the taste organ, and enhanced expression of a biosynthesizing enzyme of endocannabinoids in taste cells. The effect of LA was gradually decreased and that of AM251 was increased during the course of obesity in DIO mice. These findings suggest that circulating leptin, but not local endocannabinoids, is a dominant modulator for sweet taste in lean mice and endocannabinoids become more effective modulators of sweet taste under conditions of deficient leptin signalling.. Leptin is an anorexigenic mediator that reduces food intake by acting on hypothalamic receptor Ob-Rb. In contrast, endocannabinoids are orexigenic mediators that act via cannabinoid CB1 receptors in hypothalamus, limbic forebrain, and brainstem. In the peripheral taste system, leptin administration selectively inhibits behavioural, taste nerve and taste cell responses to sweet compounds. Opposing the action of leptin, endocannabinoids enhance sweet taste responses. However, potential roles of endogenous leptin and endocannabinoids in sweet taste remain unclear. Here, we used pharmacological antagonists (Ob-Rb: L39A/D40A/F41A (LA), CB1 : AM251) and examined the effects of their blocking activation of endogenous leptin and endocannabinoid signalling on taste responses in lean control, leptin receptor deficient db/db, and diet-induced obese (DIO) mice. Lean mice exhibited significant increases in chorda tympani (CT) nerve responses to sweet compounds after LA administration, while they showed no significant changes in CT responses after AM251. In contrast, db/db mice showed clear suppression of CT responses to sweet compounds after AM251, increased endocannabinoid (2-arachidonoyl-sn-glycerol (2-AG)) levels in the taste organ, and enhanced expression of a biosynthesizing enzyme (diacylglycerol lipase α (DAGLα)) of 2-AG in taste cells. In DIO mice, the LA effect was gradually decreased and the AM251 effect was increased during the course of obesity. Taken together, our results suggest that circulating leptin, but not local endocannabinoids, may be a dominant modulator for sweet taste in lean mice; however, endocannabinoids may become more effective modulators of sweet taste under conditions of deficient leptin signalling, possibly due to increased production of endocannabinoids in taste tissue.

Topics: Animals; Arachidonic Acids; Chorda Tympani Nerve; Endocannabinoids; Female; Glycerides; Leptin; Male; Mice, Inbred C57BL; Mice, Transgenic; Obesity; Taste; Taste Buds

There is compelling evidence in humans that peripheral endocannabinoid signaling is disrupted in obesity. However, little is known about the corresponding central signaling. Here, we have investigated the relationship between gender, leptin, body mass index (BMI) and levels of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) in the serum and cerebrospinal fluid (CSF) of primarily overweight to obese patients with osteoarthritis.. Patients (20 females, 15 males, age range 44-78 years, BMI range 24-42) undergoing total knee arthroplasty for end-stage osteoarthritis were recruited for the study. Endocannabinoids were quantified by liquid chromatography - mass spectrometry. AEA and 2-AG levels in the serum and CSF did not correlate with either age or BMI. However, 2-AG levels in the CSF, but not serum, correlated negatively with CSF leptin levels (Spearman's ρ -0.48, P=0.0076, n=30). No such correlations were observed for AEA and leptin.. In the patient sample investigated, there is a negative association between 2-AG and leptin levels in the CSF. This is consistent with pre-clinical studies in animals, demonstrating that leptin controls the levels of hypothalamic endocannabinoids that regulate feeding behavior.

Topics: Adult; Aged; Arachidonic Acids; Arthroplasty, Replacement, Knee; Body Mass Index; Chromatography, Liquid; Endocannabinoids; Female; Glycerides; Humans; Leptin; Male; Mass Spectrometry; Middle Aged; Obesity; Osteoarthritis; Polyunsaturated Alkamides

Dietary intake of linoleic acid (LNA, 18:2n-6) has increased dramatically during the 20th century and is associated with greater prevalence of obesity. The endocannabinoid system is involved in regulation of energy balance and a sustained hyperactivity of the endocannabinoid system may contribute to obesity. Arachidonic acid (ARA, 20:4n-6) is the precursor for 2-AG and anandamide (AEA), and we sought to determine if low fat diets (LFD) could be made obesogenic by increasing the endocannabinoid precursor pool of ARA, causing excessive endocannabinoid signaling leading to weight gain and a metabolic profile associated with obesity. Mice (C57BL/6j, 6 weeks of age) were fed 1 en% LNA and 8 en% LNA in low fat (12.5 en%) and medium fat diets (MFD, 35 en%) for 16 weeks. We found that increasing dietary LNA from 1 to 8 en% in LFD and MFD significantly increased ARA in phospholipids (ARA-PL), elevated 2-AG and AEA in liver, elevated plasma leptin, and resulted in larger adipocytes and more macrophage infiltration in adipose tissue. In LFD, dietary LNA of 8 en% increased feed efficiency and caused greater weight gain than in an isocaloric reduction to 1 en% LNA. Increasing dietary LNA from 1 to 8 en% elevates liver endocannabinoid levels and increases the risk of developing obesity. Thus a high dietary content of LNA (8 en%) increases the adipogenic properties of a low fat diet.

Topics: Adipose Tissue; Analysis of Variance; Animals; Arachidonic Acids; Body Weight; Diet; Diet, Fat-Restricted; Endocannabinoids; Erythrocytes; Fatty Acids; Glycerides; Leptin; Linoleic Acid; Liver; Macrophages; Male; Mice; Mice, Inbred C57BL; Obesity; Phospholipids; Polyunsaturated Alkamides; Risk Factors; Weight Gain

Acute or chronic alterations in energy status alter the balance between excitatory and inhibitory synaptic transmission and associated synaptic plasticity to allow for the adaptation of energy metabolism to new homeostatic requirements. The impact of such changes on endocannabinoid and cannabinoid receptor type 1 (CB1)-mediated modulation of synaptic transmission and strength is not known, despite the fact that this signaling system is an important target for the development of new drugs against obesity. We investigated whether CB1-expressing excitatory vs. inhibitory inputs to orexin-A-containing neurons in the lateral hypothalamus are altered in obesity and how this modifies endocannabinoid control of these neurons. In lean mice, these inputs are mostly excitatory. By confocal and ultrastructural microscopic analyses, we observed that in leptin-knockout (ob/ob) obese mice, and in mice with diet-induced obesity, orexinergic neurons receive predominantly inhibitory CB1-expressing inputs and overexpress the biosynthetic enzyme for the endocannabinoid 2-arachidonoylglycerol, which retrogradely inhibits synaptic transmission at CB1-expressing axon terminals. Patch-clamp recordings also showed increased CB1-sensitive inhibitory innervation of orexinergic neurons in ob/ob mice. These alterations are reversed by leptin administration, partly through activation of the mammalian target of rapamycin pathway in neuropeptide-Y-ergic neurons of the arcuate nucleus, and are accompanied by CB1-mediated enhancement of orexinergic innervation of target brain areas. We propose that enhanced inhibitory control of orexin-A neurons, and their CB1-mediated disinhibition, are a consequence of leptin signaling impairment in the arcuate nucleus. We also provide initial evidence of the participation of this phenomenon in hyperphagia and hormonal dysregulation in obesity.

Topics: Animals; Arachidonic Acids; Arcuate Nucleus of Hypothalamus; Endocannabinoids; Glycerides; Hypothalamus; Intracellular Signaling Peptides and Proteins; Leptin; Male; Membrane Potentials; Mice; Mice, Inbred C57BL; Mice, Obese; Microscopy, Confocal; Microscopy, Electron; Neurons; Neuropeptide Y; Neuropeptides; Obesity; Orexins; Receptor, Cannabinoid, CB1; Signal Transduction; Synaptic Transmission; TOR Serine-Threonine Kinases

Maternal obesity (MO) remains a serious obstetric problem with acute and chronic morbidities for both mothers and offspring. The mechanisms underlying these adverse consequences of MO remain unknown. Endocannabinoids (ECB) are neuromodulatory lipids released from adipocytes and other tissues. Metabolic crosstalk between placenta and adipocytes may mediate sequelae of MO. The goal of this study was to elucidate placental and systemic ECB in MO.. Placentas, sera, and subcutaneous fat were collected at Cesarean sections performed near term (0.9 G) in four non-obese (nOB) and four obese (OB) baboons (Papio spp.). Concentrations of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) were measured by liquid chromatography coupled to tandem mass spectrometry. AEA and 2-AG pathways were characterized in placentas by Q-RT-PCR, Western blot and immunohistochemistry.. Placental 2-AG levels were lower and maternal fat AEA levels were higher in OB (1254.1 ± 401.3 nmol/kg and 17.3 ± 4 nmol/kg) vs. nOB (3124.2 ± 557.3 nmol/kg and 3.1 ± 0.6 nmol/kg) animals. Concentrations of 2-AG correlated positively between maternal fat and placenta (r = 0.82, p = 0.013), but correlated negatively with maternal leptin concentrations (r = -0.72, p = 0.04 and r = -0.83, p = 0.01, respectively).. This is the first study to demonstrate differential ECB pathway regulation in maternal fat and placenta in MO. Differential regulation and function exist for AEA and 2-AG as the major ECB pathways in placenta.

Topics: Animals; Arachidonic Acids; Biological Transport; Chromatography, High Pressure Liquid; Disease Models, Animal; Endocannabinoids; Female; Gene Expression Regulation, Developmental; Glycerides; Leptin; Obesity; Papio; Placenta; Polyunsaturated Alkamides; Pregnancy; Pregnancy Complications; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Receptors, Cannabinoid; Subcutaneous Fat, Abdominal; Tandem Mass Spectrometry

Peripheral and central endocannabinoids and cognate acylethanolamides (AEs) may play important but distinct roles in regulating energy balance.. We hypothesized that in humans central/peripheral endocannabinoids are differently associated with adiposity and energy expenditure and differ by race.. We examined associations of arachindonoylethanolamide, 2-arachidonoylglycerol, palmitoylethanolamide, and oleoylethanolamide (OEA) assayed in plasma and cerebrospinal fluid (CSF) with race, adiposity, and energy expenditure.. In this monitored clinical inpatient study, CSF was obtained by lumbar puncture in 27 individuals (12 Caucasian, 11 American Indian, and four African-American). Twenty-four hour and sleep energy expenditure were measured by indirect calorimetry in a respiratory chamber.. Samples were analyzed from a previous study originally designed to test a blood-brain barrier leptin transport deficit in human obesity.. CSF (but not peripheral) 2-arachidonoylglycerol was significantly increased in American Indians compared with Caucasians (18.48 ± 6.17 vs. 10.62 ± 4.58 pmol/ml, P < 0.01). In the whole group, peripheral AEs were positively but in CSF negatively associated with adiposity. However, in multivariate models adjusted for the other peripheral and CSF AEs, peripheral arachindonoylethanolamide was the only AE significantly associated with adiposity. Interestingly, CSF OEA concentrations were positively associated with adjusted 24 hour and sleep energy expenditure (r = 0.47, P < 0.05; r = 0.42, P < 0.05), but peripheral OEA was not.. These data indicate a central alteration of the endocannabinoid system in American Indians and furthermore show that AEs in both compartments play an important but distinct role in human energy balance regulation.

Topics: Absorptiometry, Photon; Adiposity; Amides; Anti-Obesity Agents; Arachidonic Acids; Blood Glucose; Cannabinoid Receptor Modulators; Endocannabinoids; Energy Metabolism; Ethanolamines; Ethnicity; Glycerides; Humans; Insulin; Leptin; Palmitic Acids; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Receptor, Cannabinoid, CB1; Rimonabant

Acute exposure to bacterial lipopolysaccharide (LPS) is a potent inducer of immune response as well as hypophagia. Nevertheless, desensitization of responses to LPS occurs during long-term exposure to endotoxin. We induced endotoxin tolerance, injecting repeated (6LPS) LPS doses compared with single (1LPS) treatment. 1LPS, but not 6LPS group, showed decreased food intake and body weight, which was associated with an increased plasma leptin and higher mRNA expression of OB-Rb, MC4R, and SOCS3 in the hypothalamus. Hypophagia induced by 1LPS was associated with lower levels of 2-arachidonoylglycerol (2-AG), increased number of p-STAT3 neurons, and decreased AMP-activated protein kinase (AMPK) activity. Desensitization of hypophagia in the 6LPS group was related to high 2-AG, with no changes in p-STAT3 or increased p-AMPK. Leptin decreased food intake, body weight, 2-AG levels, and AMPK activity and enhanced p-STAT3 in control rats. However, leptin had no effects on 2-AG, p-STAT3, or p-AMPK in the 1LPS and 6LPS groups. Rats treated with HFD to induce leptin resistance showed neither hypophagia nor changes in p-STAT3 after 1LPS, suggesting that leptin and LPS recruit a common signaling pathway in the hypothalamus to modulate food intake reduction. Desensitization of hypophagia in response to repeated exposure to endotoxin is related to an inability of leptin to inhibit AMPK phosphorylation and 2-AG production and activate STAT3. SOCS3 is unlikely to underlie this resistance to leptin signaling in the endotoxin tolerance. The present model of prolonged inflammatory challenge may contribute to further investigations on mechanisms of leptin resistance.

Topics: Animals; Arachidonic Acids; Body Weight; Cyclic AMP-Dependent Protein Kinases; Diet; Dietary Fats; Eating; Endocannabinoids; Endotoxins; Gas Chromatography-Mass Spectrometry; Glycerides; Immunohistochemistry; Inflammation; Interleukin-10; Leptin; Lipopolysaccharides; Male; Phosphorylation; Rats; Rats, Wistar; Receptor, Melanocortin, Type 4; Receptors, Interleukin-10; Receptors, Leptin; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; STAT3 Transcription Factor; Suppressor of Cytokine Signaling 3 Protein; Suppressor of Cytokine Signaling Proteins

We previously reported that the plasma levels of the endocannabinoid, 2-arachidonoylglycerol (2-AG), in a cohort of viscerally obese men are directly correlated with visceral adipose tissue (VAT) accumulation and metabolic risk factors including low HDL-cholesterol and high triacylglycerol. It is not known, however, if such correlations persist after vigorous lifestyle interventions that reduce metabolic risk factors. We analysed the changes in endocannabinoid levels in a subsample from the same cohort following a 1 year lifestyle modification programme, and correlated them with changes in VAT and metabolic risk factors.. Forty-nine viscerally obese men (average age 49 years, BMI 30.9 kg/m(2), waist 107.3 cm) underwent a 1 year lifestyle modification programme including healthy eating and physical activity. Plasma levels of 2-AG and the other most studied endocannabinoid, anandamide, were measured by liquid chromatography-mass spectrometry. Anthropometric and metabolic risk factors, including VAT, insulin resistance and glucose intolerance, HDL-cholesterol and triacylglycerol, were measured.. Most risk factors were improved by the intervention, which led to a significant decrease in body weight (-6.4 kg, p < 0.0001), waist circumference (-8.0 cm, p < 0.0001) and VAT (-30%, p < 0.0001), and in plasma 2-AG (-62.3%, p < 0.0001) and anandamide (-7.1%, p = 0.005) levels. The decrease in levels of 2-AG but not those of anandamide correlated with decreases in VAT and triacylglycerol levels, and with the increase in HDL(3)-cholesterol levels. Multivariate analyses suggested that decreases in 2-AG and VAT were both independently associated with decreases in triacylglycerol.. This study shows that a strong correlation exists between 2-AG levels and high plasma triacylglycerol and low HDL(3)-cholesterol in viscerally obese men.

Topics: Adiponectin; Adipose Tissue; Apolipoproteins; Arachidonic Acids; Body Mass Index; Body Weight; C-Reactive Protein; Endocannabinoids; Glycerides; Humans; Interleukin-6; Leptin; Life Style; Lipids; Male; Obesity; Risk Factors; Triglycerides; Waist Circumference; Weight Loss

The hypothalamic paraventricular nucleus (PVN) integrates preautonomic and neuroendocrine control of energy homeostasis, fluid balance, and the stress response. We recently demonstrated that glucocorticoids act via a membrane receptor to rapidly cause endocannabinoid-mediated suppression of synaptic excitation in PVN neurosecretory neurons. Leptin, a major signal of nutritional state, suppresses CB(1) cannabinoid receptor-dependent hyperphagia (increased appetite) in fasting animals by reducing hypothalamic levels of endocannabinoids. Here we show that glucocorticoids stimulate endocannabinoid biosynthesis and release via a Galpha(s)-cAMP-protein kinase A-dependent mechanism and that leptin blocks glucocorticoid-induced endocannabinoid biosynthesis and suppression of excitation in the PVN via a phosphodiesterase-3B-mediated reduction in intracellular cAMP levels. We demonstrate this rapid hormonal interaction in both PVN magnocellular and parvocellular neurosecretory cells. Leptin blockade of the glucocorticoid-induced, endocannabinoid-mediated suppression of excitation was absent in leptin receptor-deficient obese Zucker rats. Our findings reveal a novel hormonal crosstalk that rapidly modulates synaptic excitation via endocannabinoid release in the hypothalamus and that provides a nutritional state-sensitive mechanism to integrate the neuroendocrine regulation of energy homeostasis, fluid balance, and the stress response.

Topics: Animals; Arachidonic Acids; Cannabinoid Receptor Modulators; Cyclic AMP; Dexamethasone; Dose-Response Relationship, Drug; Drug Interactions; Endocannabinoids; Enzyme Inhibitors; Excitatory Postsynaptic Potentials; Glucocorticoids; Glycerides; In Vitro Techniques; Leptin; Male; Neurons; Obesity; Paraventricular Hypothalamic Nucleus; Patch-Clamp Techniques; Rats; Rats, Sprague-Dawley; Rats, Zucker; Reverse Transcriptase Polymerase Chain Reaction; Synapses

The levels of the endocannabinoids anandamide and 2-arachidonoylglycerol (2-AG) are under the negative control of leptin in the rodent hypothalamus. As leptin and endocannabinoids play opposite roles in the control of reproduction, we have investigated whether the impaired fertility typical of leptin-defective ob/ob mice is due, in part, to enhanced uterine endocannabinoid levels. We found that levels of both anandamide and 2-AG in the uterus of ob/ob mice are significantly elevated with respect to wild-type littermates, due to reduced hydrolase activity in the case of anandamide, and to reduced monoacylglycerol lipase and enhanced diacylglycerol lipase activity in the case of 2-AG. Furthermore, the process mediating endocannabinoid cellular uptake was also impaired in ob/ob mice, whereas the levels of cannabinoid and anandamide receptors were not modified. Although ineffective in wild-type mice, treatment of ob/ob mice with leptin re-established endocannabinoid levels and enzyme activities back to the values observed in wild-type littermates. Finally, treatment of ob/ob females with the CB1 receptor antagonist SR141716A did not improve their fertility, and inhibition of endocannabinoid inactivation with the endocannabinoid uptake inhibitor OMDM-1 in wild-type females did not result in impaired fertility.

Topics: Animals; Arachidonic Acids; Benzyl Compounds; Cannabinoid Receptor Modulators; Endocannabinoids; Female; Fertility; Glycerides; Leptin; Lipoprotein Lipase; Mice; Mice, Knockout; Monoacylglycerol Lipases; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Receptor, Cannabinoid, CB1; Receptors, Leptin; Rimonabant; Up-Regulation; Uterus

Leptin is the primary signal through which the hypothalamus senses nutritional state and modulates food intake and energy balance. Leptin reduces food intake by upregulating anorexigenic (appetite-reducing) neuropeptides, such as alpha-melanocyte-stimulating hormone, and downregulating orexigenic (appetite-stimulating) factors, primarily neuropeptide Y. Genetic defects in anorexigenic signalling, such as mutations in the melanocortin-4 (ref. 5) or leptin receptors, cause obesity. However, alternative orexigenic pathways maintain food intake in mice deficient in neuropeptide Y. CB1 cannabinoid receptors and the endocannabinoids anandamide and 2-arachidonoyl glycerol are present in the hypothalamus, and marijuana and anandamide stimulate food intake. Here we show that following temporary food restriction, CB1 receptor knockout mice eat less than their wild-type littermates, and the CB1 antagonist SR141716A reduces food intake in wild-type but not knockout mice. Furthermore, defective leptin signalling is associated with elevated hypothalamic, but not cerebellar, levels of endocannabinoids in obese db/db and ob/ob mice and Zucker rats. Acute leptin treatment of normal rats and ob/ob mice reduces anandamide and 2-arachidonoyl glycerol in the hypothalamus. These findings indicate that endocannabinoids in the hypothalamus may tonically activate CB1 receptors to maintain food intake and form part of the neural circuitry regulated by leptin.

Topics: Animals; Appetite Regulation; Arachidonic Acids; Cannabinoid Receptor Modulators; Cannabinoids; Cerebellum; Eating; Endocannabinoids; Female; Food; Glycerides; Hypothalamus; Leptin; Lipoprotein Lipase; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Obese; Obesity; Phospholipase D; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Rats, Zucker; Receptors, Cannabinoid; Receptors, Drug; Receptors, Leptin; Rimonabant; Signal Transduction