Elevated tissue omega-3 fatty acid status prevents age-related glucose intolerance in fat-1 transgenic mice

The objective of this study was to investigate the impact of elevated tissue omega-3 (n-3) polyunsaturated fatty acids (PUFA) status on age-related glucose intolerance utilizing the fat-1 transgenic mouse model, which can endogenously synthesize n-3 PUFA from omega-6 (n-6) PUFA. Fat-1 and wild-type mice, maintained on the same dietary regime of a 10% corn oil diet, were tested at two different ages (2months old and 8months old) for various glucose homeostasis parameters and related gene expression. The older wild-type mice exhibited significantly increased levels of blood insulin, fasting blood glucose, liver triglycerides, and glucose intolerance, compared to the younger mice, indicating an age-related impairment of glucose homeostasis. In contrast, these age-related changes in glucose metabolism were largely prevented in the older fat-1 mice. Compared to the older wild-type mice, the older fat-1 mice also displayed a lower capacity for gluconeogenesis, as measured by pyruvate tolerance testing (PTT) and hepatic gene expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6 phosphatase (G6Pase). Furthermore, the older fat-1 mice showed a significant decrease in body weight, epididymal fat mass, inflammatory activity (NFκ-B and p-IκB expression), and hepatic lipogenesis (acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) expression), as well as increased peroxisomal activity (70-kDa peroxisomal membrane protein (PMP70) and acyl-CoA oxidase1 (ACOX1) expression). Altogether, the older fat-1 mice exhibit improved glucose homeostasis in comparison to the older wild-type mice. These findings support the beneficial effects of elevated tissue n-3 fatty acid status in the prevention and treatment of age-related chronic metabolic diseases

Nitric Oxide Mediates the Hormonal Control of Crassulacean Acid Metabolism Expression in Young Pineapple Plants

Genotypic, developmental, and environmental factors converge to determine the degree of Crassulacean acid metabolism (CAM) expression. To characterize the signaling events controlling CAM expression in young pineapple (Ananas comosus) plants, this photosynthetic pathway was modulated through manipulations in water availability. Rapid, intense, and completely reversible up-regulation in CAM expression was triggered by water deficit, as indicated by the rise in nocturnal malate accumulation and in the expression and activity of important CAM enzymes. During both up-and down-regulation of CAM, the degree of CAM expression was positively and negatively correlated with the endogenous levels of abscisic acid (ABA) and cytokinins, respectively. When exogenously applied, ABA stimulated and cytokinins repressed the expression of CAM. However, inhibition of water deficit-induced ABA accumulation did not block the up-regulation of CAM, suggesting that a parallel, non-ABA-dependent signaling route was also operating. Moreover, strong evidence revealed that nitric oxide (NO) may fulfill an important role during CAM signaling. Up-regulation of CAM was clearly observed in NO-treated plants, and a conspicuous temporal and spatial correlation was also evident between NO production and CAM expression. Removal of NO from the tissues either by adding NO scavenger or by inhibiting NO production significantly impaired ABA-induced up-regulation of CAM, indicating that NO likely acts as a key downstream component in the ABA-dependent signaling pathway. Finally, tungstate or glutamine inhibition of the NO-generating enzyme nitrate reductase completely blocked NO production during ABA-induced up-regulation of CAM, characterizing this enzyme as responsible for NO synthesis during CAM signaling in pineapple plants.

The sympathetic nervous system regulates the three glycerol-3P generation pathways in white adipose tissue of fasted, diabetic and high-protein diet-fed rats

The aim of the present study was to investigate the participation of the sympathetic nervous system (SNS) in the control of glycerol-3-P (G3P) generating pathways in white adipose tissue (WAT) of rats in three situations in which the plasma insulin levels are low. WAT from 48 h fasted animals, 3 day-streptozotocin diabetic animals and high-protein, carbohydrate-free (HP) diet-fed rats was surgical denervated and the G3P generation pathways were evaluated. Food deprivation, diabetes and the HP diet provoke a marked decrease in the rate of glucose uptake and glycerokinase (GyK) activity, but a significant increase in the glyceroneogenesis, estimated by the phosphoenolpyruvate carboxykinase (PEPCK) activity and the incorporation of 1-[C-14]-pyruvate into glycerol-TAG. The denervation provokes a reduction (similar to 70%) in the NE content of WAT in fasted, diabetic and HP diet-fed rats. The denervation induced an increase in WAT glucose uptake of fed, fasted, diabetic and HP diet-fed rats (40%, 60%, 3.2 fold and 35%, respectively). TAG-glycerol synthesis from pyruvate was reduced by denervation in adipocytes of fed (58%) and fasted (36%), saline-treated (58%) and diabetic (23%), and HP diet-fed rats (11%). In these same groups the denervation reduced the PEPCK mRNA expression (75%-95%) and the PEPCK activity (35%-60%). The denervation caused a similar to 35% decrease in GyK activity of control rats and a further similar to 35% reduction in the already low enzyme activity of fasted, diabetic and HP diet-fed rats. These data suggest that the SNS plays an important role in modulating G3P generating pathways in WAT, in situations where insulin levels are low. (C) 2012 Elsevier Inc. All rights reserved.

Fructose-Induced Hypothalamic AMPK Activation Stimulates Hepatic PEPCK and Gluconeogenesis due to Increased Corticosterone Levels

Fructose consumption causes insulin resistance and favors hepatic gluconeogenesis through mechanisms that are not completely understood. Recent studies demonstrated that the activation of hypothalamic 5'-AMP-activated protein kinase (AMPK) controls dynamic fluctuations in hepatic glucose production. Thus, the present study was designed to investigate whether hypothalamic AMPK activation by fructose would mediate increased gluconeogenesis. Both ip and intracerebroventricular (icv) fructose treatment stimulated hypothalamic AMPK and acetyl-CoA carboxylase phosphorylation, in parallel with increased hepatic phosphoenolpyruvate carboxy kinase (PEPCK) and gluconeogenesis. An increase in AMPK phosphorylation by icv fructose was observed in the lateral hypothalamus as well as in the paraventricular nucleus and the arcuate nucleus. These effects were mimicked by icv 5-amino-imidazole-4-carboxamide-1-beta-D-ribofuranoside treatment. Hypothalamic AMPK inhibition with icv injection of compound C or with injection of a small interfering RNA targeted to AMPK alpha 2 in the mediobasal hypothalamus (MBH) suppressed the hepatic effects of ip fructose. We also found that fructose increased corticosterone levels through a mechanism that is dependent on hypothalamic AMPK activation. Concomitantly, fructose-stimulated gluconeogenesis, hepatic PEPCK expression, and glucocorticoid receptor binding to the PEPCK gene were suppressed by pharmacological glucocorticoid receptor blockage. Altogether the data presented herein support the hypothesis that fructose-induced hypothalamic AMPK activation stimulates hepatic gluconeogenesis by increasing corticosterone levels. (Endocrinology 153: 3633-3645, 2012)

Metabolic Disorders and Adipose Tissue Insulin Responsiveness in Neonatally STZ-Induced Diabetic Rats Are Improved by Long-Term Melatonin Treatment

Diabetes mellitus is a product of low insulin sensibility and pancreatic beta-cell insufficiency. Rats with streptozotocin-induced diabetes during the neonatal period by the fifth day of age develop the classic diabetic picture of hyperglycemia, hypoinsulinemia, polyuria, and polydipsia aggravated by insulin resistance in adulthood. In this study, we investigated whether the effect of long-term treatment with melatonin can improve insulin resistance and other metabolic disorders in these animals. At the fourth week of age, diabetic animals started an 8-wk treatment with melatonin (1 mg/kg body weight) in the drinking water at night. Animals were then killing, and the sc, epididymal (EP), and retroperitoneal (RP) fat pads were excised, weighed, and processed for adipocyte isolation for morphometric analysis as well as for measuring glucose uptake, oxidation, and incorporation of glucose into lipids. Blood samples were collected for biochemical assays. Melatonin treatment reduced hyperglycemia, polydipsia, and polyphagia as well as improved insulin resistance as demonstrated by constant glucose disappearance rate and homeostasis model of assessment-insulin resistance. However, melatonin treatment was unable to recover body weight deficiency, fat mass, and adipocyte size of diabetic animals. Adiponectin and fructosamine levels were completely recovered by melatonin, whereas neither plasma insulin level nor insulin secretion capacity was improved in diabetic animals. Furthermore, melatonin caused a marked delay in the sexual development, leaving genital structures smaller than those of nontreated diabetic animals. Melatonin treatment improved the responsiveness of adipocytes to insulin in diabetic animals measured by tests of glucose uptake (sc, EP, and RP), glucose oxidation, and incorporation of glucose into lipids (EP and RP), an effect that seems partially related to an increased expression of insulin receptor substrate 1, acetyl-coenzyme A carboxylase and fatty acid synthase. In conclusion, melatonin treatment was capable of ameliorating the metabolic abnormalities in this particular diabetes model, including insulin resistance and promoting a better long-term glycemic control. (Endocrinology 153: 2178-2188, 2012)

Proteomic Analysis of Chloroplast-to-Chromoplast Transition in Tomato Reveals Metabolic Shifts Coupled with Disrupted Thylakoid Biogenesis Machinery and Elevated Energy-Production Components

A comparative proteomic approach was performed to identify differentially expressed proteins in plastids at three stages of tomato (Solanum lycopersicum) fruit ripening (mature-green, breaker, red). Stringent curation and processing of the data from three independent replicates identified 1,932 proteins among which 1,529 were quantified by spectral counting. The quantification procedures have been subsequently validated by immunoblot analysis of six proteins representative of distinct metabolic or regulatory pathways. Among the main features of the chloroplast-to-chromoplast transition revealed by the study, chromoplastogenesis appears to be associated with major metabolic shifts: (1) strong decrease in abundance of proteins of light reactions (photosynthesis, Calvin cycle, photorespiration) and carbohydrate metabolism (starch synthesis/degradation), mostly between breaker and red stages and (2) increase in terpenoid biosynthesis (including carotenoids) and stress-response proteins (ascorbate-glutathione cycle, abiotic stress, redox, heat shock). These metabolic shifts are preceded by the accumulation of plastid-encoded acetyl Coenzyme A carboxylase D proteins accounting for the generation of a storage matrix that will accumulate carotenoids. Of particular note is the high abundance of proteins involved in providing energy and in metabolites import. Structural differentiation of the chromoplast is characterized by a sharp and continuous decrease of thylakoid proteins whereas envelope and stroma proteins remain remarkably stable. This is coincident with the disruption of the machinery for thylakoids and photosystem biogenesis (vesicular trafficking, provision of material for thylakoid biosynthesis, photosystems assembly) and the loss of the plastid division machinery. Altogether, the data provide new insights on the chromoplast differentiation process while enriching our knowledge of the plant plastid proteome.

Horizontal gene transfer confers fermentative metabolism in the respiratory-deficient plant trypanosomatid Phytomonas serpens

Among trypanosomatids, the genus Phytomonas is the only one specifically adapted to infect plants. These hosts provide a particular habitat with a plentiful supply of carbohydrates. Phytomonas sp. lacks a cytochrome-mediated respiratory chain and Krebs cycle, and ATP production relies predominantly on glycolysis. We have characterised the complete gene encoding a putative pyruvate/indolepyruvate decarboxylase (PDC/IPDC) (548 amino acids) of P. serpens, that displays high amino acid sequence similarity with phytobacteria and Leishmania enzymes. No orthologous PDC/IPDC genes were found in Trypanosoma cruzi or T. brucei. Conservation of the PDC/IPDC gene sequence was verified in 14 Phytomonas isolates. A phylogenetic analysis shows that Phytomonas protein is robustly monophyletic with Leishmania spp. and C. fasciculata enzymes. In the trees this clade appears as a sister group of indolepyruvate decarboxylases of gamma-proteobacteria. This supports the proposition that a horizontal gene transfer event from a donor phytobacteria to a recipient ancestral trypanosome has occurred prior to the separation between Phytomonas. Leishmania and Crithidia. We have measured the PDC activity in P. serpens cell extracts. The enzyme has a Km value for pyruvate of 1.4 mM. The acquisition of a PDC, a key enzyme in alcoholic fermentation, explains earlier observations that ethanol is one of the major end-products of glucose catabolism under aerobic and anaerobic conditions. This represents an alternative and necessary route to reoxidise part of the NADH produced in the highly demanding glycolytic pathway and highlights the importance of this type of event in metabolic adaptation. (C) 2012 Elsevier B.V. All rights reserved.

Within-plant isoprene oxidation confirmed by direct emissions of oxidation products methyl vinyl ketone and methacrolein

Isoprene is emitted from many terrestrial plants at high rates, accounting for an estimated 1/3 of annual global volatile organic compound emissions from all anthropogenic and biogenic sources combined. Through rapid photooxidation reactions in the atmosphere, isoprene is converted to a variety of oxidized hydrocarbons, providing higher order reactants for the production of organic nitrates and tropospheric ozone, reducing the availability of oxidants for the breakdown of radiatively active trace gases such as methane, and potentially producing hygroscopic particles that act as effective cloud condensation nuclei. However, the functional basis for plant production of isoprene remains elusive. It has been hypothesized that in the cell isoprene mitigates oxidative damage during the stress-induced accumulation of reactive oxygen species (ROS), but the products of isoprene-ROS reactions in plants have not been detected. Using pyruvate-2-13C leaf and branch feeding and individual branch and whole mesocosm flux studies, we present evidence that isoprene (i) is oxidized to methyl vinyl ketone and methacrolein (iox) in leaves and that iox/i emission ratios increase with temperature, possibly due to an increase in ROS production under high temperature and light stress. In a primary rainforest in Amazonia, we inferred significant in plant isoprene oxidation (despite the strong masking effect of simultaneous atmospheric oxidation), from its influence on the vertical distribution of iox uptake fluxes, which were shifted to low isoprene emitting regions of the canopy. These observations suggest that carbon investment in isoprene production is larger than that inferred from emissions alone and that models of tropospheric chemistry and biotachemistryclimate interactions should incorporate isoprene oxidation within both the biosphere and the atmosphere with potential implications for better understanding both the oxidizing power of the troposphere and forest response to climate change.

Maternal Melatonin Programs the Daily Pattern of Energy Metabolism in Adult Offspring

Background: Shift work was recently described as a factor that increases the risk of Type 2 diabetes mellitus. In addition, rats born to mothers subjected to a phase shift throughout pregnancy are glucose intolerant. However, the mechanism by which a phase shift transmits metabolic information to the offspring has not been determined. Among several endocrine secretions, phase shifts in the light/dark cycle were described as altering the circadian profile of melatonin production by the pineal gland. The present study addresses the importance of maternal melatonin for the metabolic programming of the offspring. Methodology/Principal Findings: Female Wistar rats were submitted to SHAM surgery or pinealectomy (PINX). The PINX rats were divided into two groups and received either melatonin (PM) or vehicle. The SHAM, the PINX vehicle and the PM females were housed with male Wistar rats. Rats were allowed to mate and after weaning, the male and female offspring were subjected to a glucose tolerance test (GTT), a pyruvate tolerance test (PTT) and an insulin tolerance test (ITT). Pancreatic islets were isolated for insulin secretion, and insulin signaling was assessed in the liver and in the skeletal muscle by western blots. We found that male and female rats born to PINX mothers display glucose intolerance at the end of the light phase of the light/dark cycle, but not at the beginning. We further demonstrate that impaired glucose-stimulated insulin secretion and hepatic insulin resistance are mechanisms that may contribute to glucose intolerance in the offspring of PINX mothers. The metabolic programming described here occurs due to an absence of maternal melatonin because the offspring born to PINX mothers treated with melatonin were not glucose intolerant. Conclusions/Significance: The present results support the novel concept that maternal melatonin is responsible for the programming of the daily pattern of energy metabolism in their offspring.

Altered Glucose Homeostasis and Hepatic Function in Obese Mice Deficient for Both Kinin Receptor Genes

The Kallikrein-Kinin System (KKS) has been implicated in several aspects of metabolism, including the regulation of glucose homeostasis and adiposity. Kinins and des-Arg-kinins are the major effectors of this system and promote their effects by binding to two different receptors, the kinin B2 and B1 receptors, respectively. To understand the influence of the KKS on the pathophysiology of obesity and type 2 diabetes (T2DM), we generated an animal model deficient for both kinin receptor genes and leptin (obB1B2KO). Six-month-old obB1B2KO mice showed increased blood glucose levels. Isolated islets of the transgenic animals were more responsive to glucose stimulation releasing greater amounts of insulin, mainly in 3-month-old mice, which was corroborated by elevated serum C-peptide concentrations. Furthermore, they presented hepatomegaly, pronounced steatosis, and increased levels of circulating transaminases. This mouse also demonstrated exacerbated gluconeogenesis during the pyruvate challenge test. The hepatic abnormalities were accompanied by changes in the gene expression of factors linked to glucose and lipid metabolisms in the liver. Thus, we conclude that kinin receptors are important for modulation of insulin secretion and for the preservation of normal glucose levels and hepatic functions in obese mice, suggesting a protective role of the KKS regarding complications associated with obesity and T2DM.

Effect of inulin on the growth and metabolism of a probiotic strain of Lactobacillus rhamnosus in co-culture with Streptococcus thermophilus

Metabolic studies are very important to improve quality of functional dairy products. For this purpose, the behaviors of pure cultures of Streptococcus thermophilus (St) and Lactobacillus rhamnosus (Lr) as well a co-culture of them (St-Lr) were investigated during skim milk fermentation, and the inulin effect as prebiotic was assessed. Lr was able to metabolize 6 g/100 g more galactose than St and St-Lr. Final lactic acid production by Lr was higher (9.8 g/L) compared to St (9.1 g/L) and St-Lr (9.1 g/L). Acetic acid concentration varied from 0.8 g/L (St-Lr) to 1.5 g/L (Lr) and that of ethanol from only 0.2 g/L (St-Lr) to 0.4 g/L (Lr), which suggests the occurrence in Lr of a NADH oxidase activity and citrate co-metabolization via pyruvate, both dissipating a part of the reducing power. Diacetyl and acetoin accumulated at the highest levels (18.4 and 0.8 mg/L, respectively) with St-Lr, which suggests possible synergistic interactions between these microorganisms as well as the Lr capability of co-metabolizing citrate in the presence of lactose. Inulin stimulated both biomass growth and levels of all end-products, as the likely result of fructose release from its partial hydrolysis and subsequent metabolization as an additional carbon and energy source. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.

Melatonin acts through MT1/MT2 receptors to activate hypothalamic Akt and suppress hepatic gluconeogenesis in rats

Melatonin can contribute to glucose homeostasis either by decreasing gluconeogenesis or by counteracting insulin resistance in distinct models of obesity. However, the precise mechanism through which melatonin controls glucose homeostasis is not completely understood. Male Wistar rats were administered an intracerebroventricular (icv) injection of melatonin and one of following: an icv injection of a phosphatidylinositol 3-kinase (PI3K) inhibitor, an icv injection of a melatonin receptor (MT) antagonist, or an intraperitoneal (ip) injection of a muscarinic receptor antagonist. Anesthetized rats were subjected to pyruvate tolerance test to estimate in vivo glucose clearance after pyruvate load and in situ liver perfusion to assess hepatic gluconeogenesis. The hypothalamus was removed to determine Akt phosphorylation. Melatonin injections in the central nervous system suppressed hepatic gluconeogenesis and increased hypothalamic Akt phosphorylation. These effects of melatonin were suppressed either by icv injections of PI3K inhibitors and MT antagonists and by ip injection of a muscarinic receptor antagonist. We conclude that melatonin activates hypothalamus-liver communication that may contribute to circadian adjustments of gluconeogenesis. These data further suggest a physiopathological relationship between the circadian disruptions in metabolism and reduced levels of melatonin found in type 2 diabetes patients.

Loss of the anorexic response to systemic 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside administration despite reducing hypothalamic AMP-activated protein kinase phosphorylation in insulin-deficient rats

This study tested whether chronic systemic administration of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) could attenuate hyperphagia, reduce lean and fat mass losses, and improve whole-body energy homeostasis in insulin-deficient rats. Male Wistar rats were first rendered diabetic through streptozotocin (STZ) administration and then intraperitoneally injected with AICAR for 7 consecutive days. Food and water intake, ambulatory activity, and energy expenditure were assessed at the end of the AICAR-treatment period. Blood was collected for circulating leptin measurement and the hypothalami were extracted for the determination of suppressor of cytokine signaling 3 (SOCS3) content, as well as the content and phosphorylation of AMP-kinase (AMPK), acetyl-CoA carboxylase (ACC), and the signal transducer and activator of transcription 3 (STAT3). Rats were thoroughly dissected for adiposity and lean body mass (LBM) determinations. In non-diabetic rats, despite reducing adiposity, AICAR increased (∼1.7-fold) circulating leptin and reduced hypothalamic SOCS3 content and food intake by 67% and 25%, respectively. The anorexic effect of AICAR was lost in diabetic rats, even though hypothalamic AMPK and ACC phosphorylation markedly decreased in these animals. Importantly, hypothalamic SOCS3 and STAT3 levels remained elevated and reduced, respectively, after treatment of insulin-deficient rats with AICAR. Diabetic rats were lethargic and displayed marked losses of fat and LBM. AICAR treatment increased ambulatory activity and whole-body energy expenditure while also attenuating diabetes-induced fat and LBM losses. In conclusion, AICAR did not reverse hyperphagia, but it promoted anti-catabolic effects on skeletal muscle and fat, enhanced spontaneous physical activity, and improved the ability of rats to cope with the diabetes-induced dysfunctional alterations in glucose metabolism and whole-body energy homeostasis.

Humoral autoimmune response heterogeneity in the spectrum of primary biliary cirrhosis

Objective To compare autoantibody features in patients with primary biliary cirrhosis (PBC) and individuals presenting antimitochondria antibodies (AMAs) but no clinical or biochemical evidence of disease. Methods A total of 212 AMA-positive serum samples were classified into four groups: PBC (definite PBC, n = 93); PBC/autoimmune disease (AID; PBC plus other AID, n = 37); biochemically normal (BN) individuals (n = 61); and BN/AID (BN plus other AID, n = 21). Samples were tested by indirect immunofluorescence (IIF) on rat kidney (IIF-AMA) and ELISA [antibodies to pyruvate dehydrogenase E2-complex (PDC-E2), gp-210, Sp-100, and CENP-A/B]. AMA isotype was determined by IIF-AMA. Affinity of anti-PDC-E2 IgG was determined by 8 M urea-modified ELISA. Results High-titer IIF-AMA was more frequent in PBC and PBC/AID (57 and 70 %) than in BN and BN/AID samples (23 and 19 %) (p < 0.001). Triple isotype IIF-AMA (IgA/IgM/IgG) was more frequent in PBC and PBC/AID samples (35 and 43 %) than in BN sample (18 %; p = 0.008; p = 0.013, respectively). Anti-PDC-E2 levels were higher in PBC (mean 3.82; 95 % CI 3.36–4.29) and PBC/AID samples (3.89; 3.15–4.63) than in BN (2.43; 1.92–2.94) and BN/AID samples (2.52; 1.54–3.50) (p < 0.001). Anti-PDC-E2 avidity was higher in PBC (mean 64.5 %; 95 % CI 57.5–71.5 %) and PBC/AID samples (66.1 %; 54.4–77.8 %) than in BN samples (39.2 %; 30.9–37.5 %) (p < 0.001). PBC and PBC/AID recognized more cell domains (mitochondria, nuclear envelope, PML/sp-100 bodies, centromere) than BN (p = 0.008) and BN/AID samples (p = 0.002). Three variables were independently associated with established PBC: high-avidity anti-PDC-E2 (OR 4.121; 95 % CI 2.118–8.019); high-titer IIF-AMA (OR 4.890; 2.319–10.314); antibodies to three or more antigenic cell domains (OR 9.414; 1.924–46.060). Conclusion The autoantibody profile was quantitatively and qualitatively more robust in definite PBC as compared with AMA-positive biochemically normal individuals.

Reduced endothelium-dependent relaxation to anandamide in mesenteric arteries from young obese Zucker rats

Impaired vascular function, manifested by an altered ability of the endothelium to release endothelium-derived relaxing factors and endothelium-derived contracting factors, is consistently reported in obesity. Considering that the endothelium plays a major role in the relaxant response to the cannabinoid agonist anandamide, the present study tested the hypothesis that vascular relaxation to anandamide is decreased in obese rats. Mechanisms contributing to decreased anandamide-induced vasodilation were determined. Resistance mesenteric arteries from young obese Zucker rats (OZRs) and their lean counterparts (LZRs) were used. Vascular reactivity was evaluated in a myograph for isometric tension recording. Protein expression and localization were analyzed by Western blotting and immunofluorescence, respectively. Vasorelaxation to anandamide, acetylcholine, and sodium nitroprusside, as well as to CB1, CB2, and TRPV1 agonists was decreased in endothelium-intact mesenteric arteries from OZRs. Incubation with an AMP-dependent protein kinase (AMPK) activator or a fatty acid amide hydrolase inhibitor restored anandamide-induced vascular relaxation in OZRs. CB1 and CB2 receptors protein expression was decreased in arteries from OZRs. Incubation of mesenteric arteries with anandamide evoked endothelial nitric oxide synthase (eNOS), AMPK and acetyl CoA carboxylase phosphorylation in LZRs, whereas it decreased phosphorylation of these proteins in OZRs. In conclusion, obesity decreases anandamide-induced relaxation in resistance arteries. Decreased cannabinoid receptors expression, increased anandamide degradation, decreased AMPK/eNOS activity as well as impairment of the response mediated by TRPV1 activation seem to contribute to reduce responses to cannabinoid agonists in obesity.