Extending the glucose/fatty acid cycle: a glucose/adipose tissue cycle

2003 ◽  
Vol 31 (6) ◽  
pp. 1161-1164 ◽  
Author(s):  
M. Guerre-Millo
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Leptin Resistance ◽  
Acid Oxidation ◽  
Peripheral Tissues ◽  
Kinase Activation ◽  
Glucose Fatty Acid Cycle ◽  
Sensitizing Effect ◽  
Factor Α

It is now recognized that the WAT (white adipose tissue) produces a variety of bioactive peptides, collectively termed ‘adipokines’. Alteration of WAT mass in obesity or lipoatrophy affects the production of most adipose secreted factors. Since both conditions are associated with insulin resistance, the idea has emerged that certain adipokines might influence insulin action. Among these, tumour necrosis factor α, interleukin-6 and resistin are increased in the obese state and interfere negatively with insulin-mediated processes. Conversely, leptin and adiponectin exert an insulin-sensitizing effect, at least in part by favouring tissue fatty-acid oxidation through AMP-activated kinase activation. Obesity-induced insulin resistance has been linked to leptin resistance and decreased plasma adiponectin, while administration of leptin and adiponectin normalizes plasma levels in lipoatrophic mice and reverses insulin resistance. Thiazolidinedione anti-diabetic agents increase endogenous adiponectin production in rodents and humans, supporting the idea that drugs targeting adipokines might represent a new therapeutic approach to sensitize peripheral tissues to insulin.

scholarly journals Fatty acid metabolism in obesity and type 2 diabetes mellitus

2003 ◽  
Vol 62 (3) ◽  
pp. 753-760 ◽  
Author(s):  
E. E. Blaak
Keyword(s):  
Diabetes Mellitus ◽  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Type 2 Diabetes Mellitus ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Acid Oxidation ◽  
Acid Uptake

Disturbances in pathways of lipolysis and fatty acid handling are of importance in the aetiology of obesity and type 2 diabetes mellitus. There is evidence that a lowered catecholamine-mediated lipolytic response may play a role in the development and maintenance of increased adipose tissue stores. Increased adipose tissue stores, a disturbed insulin-mediated regulation of lipolysis and subnormal skeletal muscle non-esterified fatty acid (NEFA) uptake under conditions of high lipolytic rate may increase circulating NEFA concentrations, which may promote insulin resistance and cardiovascular complications. In addition, a disturbance of NEFA uptake by adipose tissue postprandially is also a critical determinant of plasma NEFA concentration. Furthermore, evidence is increasing that insulin-resistant muscle is characterised by a lowered ability to oxidise fatty acids. A dysbalance between fatty acid uptake and fatty acid oxidation may in turn be a factor promoting accumulation of lipid intermediates and triacylglycerols within skeletal muscle, which is strongly associated with skeletal muscle insulin resistance. The present review describes the reported disturbances in pathways of lipolysis and skeletal muscle fatty acid handling, and discusses underlying mechanisms and metabolic consequences of these disturbances.

scholarly journals Protectin DX attenuates LPS-induced inflammation and insulin resistance in adipocytes via AMPK-mediated suppression of the NF-κB pathway

2018 ◽  
Vol 315 (4) ◽  
pp. E543-E551 ◽  
Author(s):  
Tae Woo Jung ◽  
Yoon Hee Chung ◽  
Hyoung-Chun Kim ◽  
A. M. Abd El-Aty ◽  
Ji Hoon Jeong
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Cell Types ◽  
Acid Oxidation ◽  
Dependent Manner ◽  
Monocyte Chemoattractant Protein 1 ◽  
Ampk Phosphorylation ◽  
Protectin Dx ◽  
Factor Α ◽  
Interfering Rna

Several studies have demonstrated that protectins, ω-3 fatty acid-derived proresolution mediators, may ameliorate inflammation. Recently, protectin DX (PDX) was also reported to attenuate inflammation and insulin resistance in several cell types. However, the effects of PDX on inflammation in adipocytes remain ambiguous. In this study, we found that PDX treatment suppressed adipogenesis and lipid accumulation during 3T3-L1 differentiation. Treatment of differentiated 3T3-L1 cells with PDX stimulated AMP-activated protein kinase (AMPK) phosphorylation in a dose-dependent manner. PDX-induced AMPK phosphorylation blocked lipopolysaccharide (LPS)-induced secretion of proinflammatory cytokines, such as tumor necrosis factor-α and monocyte chemoattractant protein-1. Treatment of 3T3-L1 cells with PDX alleviated LPS-induced NF-κB and inhibitory factor κB phosphorylation. Furthermore, PDX treatment diminished LPS-induced impairment of insulin signaling and insulin-stimulated glucose uptake, as well as fatty acid oxidation. These effects were decreased by silencing AMPK expression with small-interfering RNA. In conclusion, the current findings suggest that PDX attenuates inflammation and insulin resistance in adipocytes via an AMPK-dependent pathway, which in turn provides evidence that PDX has anti-inflammatory and antidiabetic effects in adipocytes.

scholarly journals Chronic cold exposure induces autophagy to promote fatty acid oxidation, mitochondrial turnover, and thermogenesis in brown adipose tissue

iScience ◽  
2021 ◽  
pp. 102434
Author(s):  
Winifred W. Yau ◽  
Kiraely Adam Wong ◽  
Jin Zhou ◽  
Nivetha Kanakaram Thimmukonda ◽  
Yajun Wu ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Oxidation ◽  
Cold Exposure ◽  
Acid Oxidation ◽  
Brown Adipose ◽  
Mitochondrial Turnover

scholarly journals Adiponectin Controls Nutrient Availability in Hypothalamic Astrocytes

2021 ◽  
Vol 22 (4) ◽  
pp. 1587
Author(s):  
Nuri Song ◽  
Da Yeon Jeong ◽  
Thai Hien Tu ◽  
Byong Seo Park ◽  
Hye Rim Yang ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Adipose Tissue ◽  
Nutrient Availability ◽  
Acid Oxidation ◽  
Cell Type ◽  
Metabolic Processes ◽  
Nutrient Metabolism ◽  
Peripheral Tissues ◽  
The Central Nervous System

Adiponectin, an adipose tissue-derived hormone, plays integral roles in lipid and glucose metabolism in peripheral tissues, such as the skeletal muscle, adipose tissue, and liver. Moreover, it has also been shown to have an impact on metabolic processes in the central nervous system. Astrocytes comprise the most abundant cell type in the central nervous system and actively participate in metabolic processes between blood vessels and neurons. However, the ability of adiponectin to control nutrient metabolism in astrocytes has not yet been fully elucidated. In this study, we investigated the effects of adiponectin on multiple metabolic processes in hypothalamic astrocytes. Adiponectin enhanced glucose uptake, glycolytic processes and fatty acid oxidation in cultured primary hypothalamic astrocytes. In line with these findings, we also found that adiponectin treatment effectively enhanced synthesis and release of monocarboxylates. Overall, these data suggested that adiponectin triggers catabolic processes in astrocytes, thereby enhancing nutrient availability in the hypothalamus.

Isotope tracer measures of meal fatty acid metabolism: reproducibility and effects of the menstrual cycle

2005 ◽  
Vol 288 (3) ◽  
pp. E547-E555 ◽  
Author(s):  
Ana Paola Uranga ◽  
James Levine ◽  
Michael Jensen
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Menstrual Cycle ◽  
Dietary Fat ◽  
Fatty Acid Uptake ◽  
Upper Body ◽  
Acid Oxidation ◽  
Acid Uptake ◽  
Lower Body

Oxidation and adipose tissue uptake of dietary fat can be measured by adding fatty acid tracers to meals. These studies were conducted to measure between-study variability of these types of experiments and assess whether dietary fatty acids are handled differently in the follicular vs. luteal phase of the menstrual cycle. Healthy normal-weight men ( n = 12) and women ( n = 12) participated in these studies, which were block randomized to control for study order, isotope ([3H]triolein vs. [14C]triolein), and menstrual cycle. Energy expenditure (indirect calorimetry), meal fatty acid oxidation, and meal fatty acid uptake into upper body and lower body subcutaneous fat (biopsies) 24 h after the experimental meal were measured. A greater portion of meal fatty acids was stored in upper body subcutaneous adipose tissue (24 ± 2 vs. 16 ± 2%, P < 0.005) and lower body fat (12 ± 1 vs. 7 ± 1%, P < 0.005) in women than in men. Meal fatty acid oxidation (3H2O generation) was greater in men than in women (52 ± 3 vs. 45 ± 2%, P = 0.04). Leg adipose tissue uptake of meal fatty acids was 15 ± 2% in the follicular phase of the menstrual cycle and 10 ± 1% in the luteal phase ( P = NS). Variance in meal fatty acid uptake was somewhat ( P = NS) greater in women than in men, although menstrual cycle factors did not contribute significantly. We conclude that leg uptake of dietary fat is slightly more variable in women than in men, but that there are no major effects of menstrual cycle on meal fatty acid disposal.

scholarly journals MicroRNA-27b-3p regulates function and metabolism in insulin resistance cells by inhibiting receptor tyrosine kinase-like orphan receptor 1

2018 ◽  
Vol 16 ◽  
pp. 205873921876205
Author(s):  
Yong Liu ◽  
Guohui Wang ◽  
Xiangwu Yang ◽  
Pengzhou Li ◽  
Hao Ling ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Tyrosine Kinase ◽  
Glucose Uptake ◽  
Fatty Acid Oxidation ◽  
Receptor Tyrosine Kinase ◽  
Cell Model ◽  
Orphan Receptor ◽  
Acid Oxidation ◽  
Metabolism Disorder

Type 2 diabetes mellitus (T2DM) is associated with insulin resistance-induced lipid and glucose metabolism disorder. The study was aimed to explore the potential functional role of microRNA (miR)-27b-3p in T2DM, as well as underlying mechanisms. An insulin resistance cell model was induced in HepG2 cells and then expression of miR-27b-3p and receptor tyrosine kinase-like orphan receptor 1 (ROR1) was analyzed. The expression of miR-27b-3p was overexpressed or silenced, and the relationship between ROR1 and miR-27b-3p was investigated. Thereafter, the effects of miR-27b-3p on percentage of glucose uptake, fatty acid oxidation and cell cycle were analyzed. The expressions of miR-27b-3p were significantly increased, while the ROR1 levels were statistically decreased in the cells of the model group. Overexpression of miR-27b-3p dramatically decreased the levels of ROR1 and the percentage of glucose uptake, but had no effects on fatty acid oxidation. ROR1 was a target of miR-27b-3p. Moreover, overexpression of miR-27b-3p could remarkably highlight the percentages of cells at G0/G1 phase, but decreased the percentages of cells at S phase. In conclusion, our results suggest that miR-27b-3p regulates the function and metabolism of insulin resistance cells by inhibiting ROR1. miR-27b-3p might be a potential drug target in treating T2DM.

Effect of adipocyte β3-adrenergic receptor activation on the type 2 diabetic MKR mice

2006 ◽  
Vol 290 (6) ◽  
pp. E1227-E1236 ◽  
Author(s):  
Hyunsook Kim ◽  
Patricia A. Pennisi ◽  
Oksana Gavrilova ◽  
Stephanie Pack ◽  
William Jou ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Receptor Activation ◽  
Whole Body ◽  
Acid Oxidation ◽  
Adrenergic Agonists ◽  
Nonobese Diabetic ◽  
Type 2 Diabetic

The antiobesity and antidiabetic effects of the β3-adrenergic agonists were investigated on nonobese type 2 diabetic MKR mice after injection with a β3-adrenergic agonist, CL-316243. An intact response to acute CL-316243 treatment was observed in MKR mice. Chronic intraperitoneal CL-316243 treatment of MKR mice reduced blood glucose and serum insulin levels. Hyperinsulinemic euglycemic clamps exhibited improvement of the whole body insulin sensitivity and glucose homeostasis concurrently with enhanced insulin action in liver and adipose tissue. Treating MKR mice with CL-316243 significantly lowered serum and hepatic lipid levels, in part due to increased whole body triglyceride clearance and fatty acid oxidation in adipocytes. A significant reduction in total body fat content and epididymal fat weight was observed along with enhanced metabolic rate in both wild-type and MKR mice after treatment. These data demonstrate that β3-adrenergic activation improves the diabetic state of nonobese diabetic MKR mice by potentiation of free fatty acid oxidation by adipose tissue, suggesting a potential therapeutic role for β3-adrenergic agonists in nonobese diabetic subjects.

scholarly journals Specific shifts in the endocannabinoid system in hibernating brown bears

2020 ◽  
Author(s):  
Christian Boyer ◽  
Laura Cussonneau ◽  
Charlotte Brun ◽  
Christiane Deval ◽  
Jean-Paul Pais de Barros ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Ursus Arctos ◽  
Mild Hypothermia ◽  
Endocannabinoid System ◽  
Fold Increase ◽  
Physiological Adaptation ◽  
Acid Oxidation ◽  
Brown Bears ◽  
Peripheral Tissues ◽  
Free Ranging

Abstract In small hibernators, global downregulation of the endocannabinoid system (ECS), which is involved in modulating neuronal signaling, feeding behavior, energy metabolism, and circannual rhythms, has been reported to possibly drive physiological adaptation to the hibernating state. We hypothesized that specific changes should occur in hibernating brown bears ( Ursus arctos ) due to specific features, including hibernation during half the year at only mild hypothermia while remaining physically inactive without drinking or eating, and the absence of arousal episodes although bears remain sensitive to external disturbances. We explored circulating lipids and the ECS in plasma and metabolically active tissues (muscle and adipose tissue), in free-ranging subadult Scandinavian brown bears when both active and hibernating. In winter bear serum, in addition to a 2-fold increase in total fatty acid concentration, we found significant changes in relative proportions of circulating fatty acids, such as a 2-fold increase in docosahexaenoic acid and a decrease in arachidonic acid. In adipose and muscle tissues of hibernating bears, we found lower concentrations of both two major ligands for endocannabinoid receptors, 2-arachidonoylglycerol (2-AG) and anandamide (AEA). Gene expression was reduced for enzymes that synthesize endocannabinoid compounds, whereas an increase was observed for catabolic enzymes. Reduction in ECS tone may promote mobilization of fat stores and favor carbohydrate metabolism in skeletal muscle of hibernating bears. Additionally, high circulating of the endocannabinoid-like compound N-oleoylethanolamide (OEA) in winter could favor lipolysis and fatty acid oxidation in peripheral tissues. We also speculated on a role of OEA in the maintenance of torpor (reduction in locomotion), while promoting the capacity of bears to sense stimuli from the environment.

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