Proc Thermogenessi Acad Higher metabolism rate Thermogenesis process explained ; : esplained Snitker S, Macdonald I, Ravussin E, Astrup A. Thus, the Fuel Efficiency Monitoring and Control pieces become hypoxic when stimulated [ 30 ] and measurement of thermogenesis in this type of preparation is therefore not meaningful. The intestinal absorption of nutrients, the initial steps of their metabolism and the storage of the absorbed but not immediately oxidized nutrients [ 15 ]. PubMed Google Scholar.

Thermogenesis process explained -

Heat Stroke. Heat Treatments. Heat-Related Injuries. NEARBY TERMS thermodynamic. Thermo King Corporation. Thermo Instrument Systems Inc. Thermo Fibertek, Inc. Thermo Electron Corporation.

Thermo BioAnalysis Corp. thermic effect of food. Thermes, Jennifer thermal window. thermal wind. thermal unit. thermogenic drugs. thermoluminescent dating. thermoneutral zone.

thermonuclear energy. thermonuclear reactions. thermophilous species. Thermoregulation, Exercise, and Thirst. Thermoregulatory System. thermoremanent magnetism. thermoremanent magnetization.

Thermos Company. Thermosbaenacea Thermosbaenaceans. Thermosbaenaceans: Thermosbaenacea. At the heart of thermogenic regulation and lipid processing is the mitochondrion, which is the site of the UCP1 function and lipid catabolism through β-oxidation.

Mitochondria are highly abundant in brown and beige adipocytes and take on distinct morphology and inter-organelle interactions upon cold stimulation [ 7 ]. Thermogenesis in brown and beige adipocytes is dependent on mitochondrial lipid processing.

These lipids can be produced directly in brown and beige adipocytes or can come from peripheral sources including white adipocytes or the liver. Lipids generated in the brown and beige adipocytes that alter mitochondrial function include CLs, 12,diHOMEs, and plasmalogens.

Peripherally produced lipids and lipid complexes enter the circulation and are taken up by thermogenic adipocytes including acylcarnitines and triglyceride-rich lipoproteins [ 8 ] [ 9 ].

Other lipids have numerous sources including FFAs and the lipid-derived metabolite ketones. FFAs primarily come from white adipose tissue lipolysis but can also come from brown and beige adipocytes.

Many lipids have several roles, such as cardiolipins that provide structural support to mitochondrial membranes, stabilize UCP1, and signal to the nucleus for transcriptional regulation [ 10 ].

Similarly, ketones are an important fuel substrate but also regulate beige adipocyte differentiation. The ability of lipids to play numerous roles highlights the dynamic nature of these molecules and emphasizes the need to reassess our limited view of lipids as single purpose molecules. We have limited the scope of this review to focus on lipids that are produced by or impact mitochondria in the brown and beige adipocytes.

There are several lipids that impact thermogenesis that were left out due to this narrow designation including sphingolipids, dolichols, diacylglycerols, prostaglandins, and hydroxyeicosapentaenoic acid HEPE [ 11 ] [ 12 ] [ 13 ]. Some of these lipids function through mechanisms that impact mitochondria only in a secondary manner such as HEPE, which activates G-protein coupled receptors to increase glucose uptake in brown adipocytes [ 13 ].

Other lipids potentially have a role in mitochondrial regulation, such as sphingolipids and ceramides, but the exact mechanism of this action is yet to be understood. Recent work demonstrated that a UCP1-cre mediated knockout of serine palmitoyltransferase subunit 2, an enzyme important in ceramide synthesis, led to increased mitochondrial density, while knockout of an enzyme in ceramide degradation led to reduced mitochondrial density [ 14 ].

Further exploration into the mechanisms by which ceramides are driving these mitochondrial differences is needed. Another subset of these lipids impacts the conversion of white adipocytes to beige adipocytes such as prostaglandin H2, but the direct regulation of mitochondria function and thermogenesis is unexplored [ 6 ].

The importance of prostaglandins in thermoregulation warrants further investigation, but their known regulation of body temperature for fevers is intriguing.

Physiological factors such as sex or age influence the lipid composition of brown adipocytes. The lipidomic analysis of BAT from female or male mice revealed sex-specific differences in phospholipid acyl chains, with more incorporation of stearic and arachidonic acid in females, and palmitic and linoleic acid in males [ 15 ].

Increased desaturation of mitochondrial phospholipids impacts membrane dynamics and may underly the dimorphism in the mitochondrial size and shape observed between male and female BAT in rats [ 16 ].

Aging also alters BAT lipid metabolism. In the BAT of aged mice, decreased production of lipoic acid leads to suppression of catabolic pathways including fatty acid oxidation [ 17 ].

It was also seen that as mice age, their capacity to regulate body temperature during cold exposure is limited because of reduced acylcarnitine production in the liver.

When acylcarnitines were administered to aged mice during cold exposure, BAT thermogenesis improved [ 9 ]. How lipid-based signaling in BAT is impacted by sex and age requires further study. More work is needed to understand lipids that impact mitochondria in beige adipocytes.

This is difficult because the emergence of beige adipocytes in subcutaneous adipose tissue is heterogeneous and occurs in pockets surrounding vasculature [ 18 ].

Moreover, the advent of single cell and single nuclei RNA sequencing, as well as the refinement of cold stress conditions, have demonstrated that there are numerous subtypes of beige adipocyte that have differences in glycolytic capacity and cellular origin [ 19 ] [ 20 ] [ 21 ] [ 22 ].

These studies have also revealed lipid signaling between beige adipocytes and resident macrophages that regulates the thermogenic response [ 20 ] [ 23 ]. The advent of single cell metabolomics coupled with cell sorting will enable the exploration of the lipid composition of individual subtypes of beige adipocytes [ 24 ].

At the cellular level, several emerging technologies have led to higher lipid visualization and quantitation. Mass-spectrometry-based lipidomics has unearthed previously unidentified lipids including signaling molecules such as fatty acid esters of hydroxy fatty acids FAHFAs , which regulate insulin sensitivity [ 25 ] [ 26 ].

Chemical probes including photoswitches have the capacity to functionally characterize lipids and the proteins they interact with, while photocleavable groups can facilitate the temporal range of lipid activity [ 27 ].

Labels including fluorescent tags such as Bodipy and GFP as well as luminescent tags on acyl-chains provide imaging potential to determine cellular localization and lipid uptake [ 28 ] [ 29 ] [ 30 ].

Further tools are needed to increase the capacity to track lipid mobility and uptake in vivo to determine novel inter-organ communication pathways. Currently, quantitative assessment of lipid mobility is through radioactive or heavy isotope labeling.

Radioactivity is sensitive and can be used to assess lipid uptake from the circulation and quantitatively assess oxidation but can be difficult to use in vivo.

Heavy isotope labeling is cost prohibitive in vivo and the expertise for the quantitative calculation of pathway input is limited to several labs around the world [ 31 ] [ 32 ]. Both technologies are limited in their ability to assess inter-organ signaling pathways.

As these tools are developed and applied in tandem, they will expand our depth of understanding for the importance of lipid metabolism in thermogenic adipose tissue. Encyclopedia Scholarly Community. Entry Journal Book Video Image About Entry Entry Video Image.

Submitted Successfully! Thank you for your contribution! You can also upload a video entry or images related to this topic. Version Summary Created by Modification Content Size Created at Operation 1 Judith Simcox. Vicky Zhou. Video Upload Options Do you have a full video? Send video materials Upload full video.

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Copy Citation. Home Entry Topic Review Current: Thermogenesis. This entry is adapted from the peer-reviewed paper brown adipose tissue thermogenesis mitochondria lipids.

Introduction Body temperature regulation is a selective advantage that has allowed endotherms to thrive in diverse climates. Mitochondrial Lipid Signaling and Adaptive Thermogenesis Thermogenesis in brown and beige adipocytes is dependent on mitochondrial lipid processing.

References Kajimura, S. Brown and Beige Fat: Physiological Roles beyond Heat Generation. Cell Metab. Cannon, B. Brown adipose tissue: Function and physiological significance. Roesler, A.

UCP1-independent thermogenesis. Rosen, E. Adipocytes as regulators of energy balance and glucose homeostasis. Nature , , — Park, H. Lipid Regulators of Thermogenic Fat Activation. Trends Endocrinol. TEM , 30, — Lynes, M. Lipokines and Thermogenesis.

Endocrinology , , — Wikstrom, J. Hormone-induced mitochondrial fission is utilized by brown adipocytes as an amplification pathway for energy expenditure.

Thank you for visiting nature. Themrogenesis are using a browser Thermovenesis with limited support for CSS. To Thermogenesis process explained the best experience, we Brain health Broccoli and cheese recipes use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. A basic property of endothermic thermoregulation is the ability to generate heat by increasing metabolism in response to cold ambient temperatures to maintain a stable core body temperature. Explaied use Fuel Efficiency Monitoring and Control and similar technologies to provide Fuel Efficiency Monitoring and Control best experience on esplained website. Thermogenwsis to Importance of gut health Privacy Policy for more information. Complete Guide to Cupping and its Benefits. The Complete Guide to Fat Oxidation. Close 🍪 Cookie Policy We use cookies and similar technologies to provide the best experience on our website. Accept Decline.

Thermogenesis process explained -

Furthermore, expression of GH and the GH secretagogue receptor GHSR is greater in genetically lean sheep, indicating differential responses to ghrelin, an agonist of the GHSR French et al.

This suggests that innate differences in the set-point of the GH axis may underpin differences in adiposity in the genetically lean and obese sheep; however, this is only one aspect that could contribute to this phenotype. Interestingly, food intake is similar in genetically lean and obese sheep as is the expression of POMC, Leptin Receptor and NPY in the arcuate nucleus.

On the other hand, lean animals have elevated post-prandial thermogenesis in retroperitoneal adipose tissue and this coincides with increased expression of UCP1 in this tissue Henry et al. The divergence in thermogenesis is specific to adipose tissue since post-prandial thermogenesis is similar in genetically lean and obese animals Henry et al.

Despite similar expression of appetite-regulating peptides in the arcuate nucleus of the hypothalamus, genetically lean sheep have increased expression of MCH and pre-pro-orexin ORX in the LH compared to obese animals Anukulkitch et al.

While both neuropeptides are considered orexigenic Shimada et al. Deletion of MCH in mice results in hypophagia and a lean phenotype Shimada et al.

Orexin is critical in the embryonic development of BAT in mice Sellayah et al. Thus, increased expression of ORX in the LH of lean sheep may be an important physiological determinant of increased thermogenesis in retroperitoneal fat and the associated changes in adiposity.

It is widely recognised that there is marked variation in the glucocorticoid response to stress or activation of the hypothalamo-pituitary adrenal HPA axis Cockrem , Walker et al. The activity of the HPA axis in response to stress is impacted on by age Sapolsky et al. Nonetheless, in any given population individuals can be characterised as either high HR or low LR glucocorticoid responders Epel et al.

It is important to note that female LR and HR sheep have similar basal plasma cortisol concentration and divergence in glucocorticoid secretion only occurs in response to ACTH or stress Lee et al. Previous studies have suggested that obesity itself causes perturbation of the HPA axis with impaired glucocorticoid-negative feedback Jessop et al.

Furthermore, cortisol directly impacts on metabolic function; however, this will not be addressed in the current review. Initial studies in rams show that high cortisol response to adrenocorticotropin ACTH is associated with lower feed-conversion efficiency Knott et al.

Furthermore, in rams, adiposity is correlated to cortisol responses to ACTH Knott et al. More recent work shows that identification of high HR and low LR cortisol responders in female sheep can predict altered propensity to gain weight when exposed to a high-energy diet, where HR gain more adipose tissue than LR Lee et al.

Thus, at least in female sheep, data suggest that cortisol responses can be used as a physiological marker that predicts propensity to become obese. Previous studies in women suggest that HR eat more after a stressful episode than LR Epel et al.

Furthermore, HR individuals display preference for foods of high fat and sugar in response to psychological stress Tomiyama et al. Similarly, in ewes, baseline food intake is similar in LR and HR, but HR eat more following either psychosocial barking dog or immune lipopolysaccharide exposure stressors Lee et al.

In addition to altered food intake, HR ewes have reduced thermogenesis in skeletal muscle only; in response to meal feeding, post-prandial thermogenesis in skeletal muscle is greater in LR than in HR Lee et al. This again exemplifies divergence in the control of adipose tissue and skeletal muscle thermogenesis Fig.

Schematic depiction of the altered metabolic phenotype in animals selected for either high or low cortisol responsiveness.

Sheep are characterised as either high HR or low LR cortisol responders when given a standardised dose of adrenocorticotropic hormone. Animals characterized as HR have increased propensity to become obese, which is associated with perturbed control of food intake and reduced energy expenditure.

Post-prandial thermogenesis in skeletal muscle is decreased in HR compared to LR ewes. Furthermore, food intake in response to stress is greater in HR than in LR and the former are resistant to the satiety effect of alpha-melanocyte stimulating hormone aMSH.

High-cortisol-responding animals have reduced expression of the melanocortin 4 receptor MC4R in the paraventricular nucleus of the hypothalamus PVN. We propose that the decreased levels of MC4R underpin the altered metabolic phenotype and increased propensity to become obese when compared to LR.

For example, at baseline in the non-stressed resting state, HR individuals show an overall upregulation of the HPA axis, with increased expression of CRF and arginine vasopressin, but reduced expression of oxytocin in the PVN Hewagalamulage et al.

In addition to altered expression of genes within the HPA axis, a key neuroendocrine feature of the LR and HR animals is altered expression of the MC3R and MC4R in the PVN Fig. Reduced MC4R expression coincides with the development of melanocortin resistance.

Central infusion of leptin reduces food intake in both LR and HR animals, but intracerebroventricular infusion of aMSH reduces food intake in LR only. Thus, reduced MC4R expression appears to be central to the metabolic phenotype of HR that confers increased propensity to become obese in HR individuals Fig.

Interestingly, gene expression of NPY , AgRP and POMC in the arcuate nucleus is equivalent in LR and HR Hewagalamulage et al. Hence, differences in the control of food intake and thermogenesis are most likely manifest at the level of the melanocortin receptor.

Indeed, previous work in sheep has shown the MC4R to be central in mediating the reduction in food intake caused by immune challenge Sartin et al. Furthermore, in rodents, direct injection of the melanocortin agonist melanotan II into the ventromedial nucleus of the hypothalamus increases skeletal muscle thermogenesis Gavini et al.

We propose that reduced expression of the MC4R in HR animals underpins the metabolic phenotype wherein food intake is relatively increased in response to stress and reduced post-prandial thermogenesis in skeletal muscle is associated with propensity to become obese. Historically, thermogenesis was considered to primarily occur in brown adipocytes and was solely driven by UCP1.

It is now recognised that beige adipocytes and skeletal muscle also contribute to total thermogenic capacity and that thermogenesis is differentially regulated in these tissues. Indeed, in beige adipocytes, thermogenesis occurs via three distinct mechanisms, with these being UCP1-driven mitochondrial uncoupling, futile creatine cycling and futile calcium cycling.

On the other hand, in skeletal muscle, thermogenesis is associated with UCP3 and futile calcium cycling. Unlike rodents, large mammals including sheep and pigs do not contain a defined or circumscribed brown fat depot but have dispersed brown adipocytes within traditionally white fat depots.

Large animals have provided invaluable insight into alternative mechanisms of thermogenesis. The sheep has been particularly useful in delineating the differential role of adipose tissue and skeletal muscle in the control of body weight.

Furthermore, sheep models have allowed characterisation of the neuroendocrine pathways that may contribute to altered thermogenesis. We have shown that in sheep, both skeletal muscle and BAT differentially contribute to thermogenesis and therefore total energy expenditure.

Changes in thermogenesis, however, do not exclusively associate with altered gene expression at the level of the arcuate nucleus. Indeed, decreased MC4R expression in HR animals and reduced orexin expression in the genetically obese animals coincide with altered thermogenic output.

This review highlights the importance of the use of large animal models to ascertain the contribution and control of thermogenesis in multiple tissues and the relative role in the regulation of body weight.

The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of this review. This work was supported by Australian Research Council grant number DP and National Health and Medical Research Council grant number APP Animal Science 63 — Journal of Pathology and Bacteriology 91 — Obesity Reviews 19 — Molecular Metabolism 5 — Neuroendocrinology 91 — Biochimica et Biophysica Acta — Astrup A Thermogenesis in human brown adipose tissue and skeletal muscle induced by sympathomimetic stimulation.

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Handbook of Experimental Pharmacology — Domestic Animal Endocrinology 34 — You Might Also Like Thermoregulation.

Heat Cramps. Injury: Heat Stroke. Heat Stroke. Heat Treatments. Heat-Related Injuries. NEARBY TERMS thermodynamic. Thermo King Corporation. Thermo Instrument Systems Inc. Thermo Fibertek, Inc. Thermo Electron Corporation. Thermo BioAnalysis Corp. thermic effect of food.

Thermes, Jennifer thermal window. thermal wind. thermal unit. thermogenic drugs. Thermogenesis is the process of heat production in organisms.

It occurs in all warm-blooded animals, and also in a few species of thermogenic plants such as the Eastern skunk cabbage , the Voodoo lily Sauromatum venosum , and the giant water lilies of the genus Victoria.

The lodgepole pine dwarf mistletoe, Arceuthobium americanum , disperses its seeds explosively through thermogenesis. Depending on whether or not they are initiated through locomotion and intentional movement of the muscles , thermogenic processes can be classified as one of the following:.

One method to raise temperature is through shivering. It produces heat because the conversion of the chemical energy of ATP into kinetic energy causes almost all of the energy to show up as heat.

Shivering is the process by which the body temperature of hibernating mammals such as some bats and ground squirrels is raised as these animals emerge from hibernation. Non-shivering thermogenesis occurs in brown adipose tissue brown fat [3] that is present in almost all eutherians swine being the only exception currently known [4] [5].

The structure has the typical fold of a member of the SLC25 family. This uncouples oxidative phosphorylation , and the energy from the proton motive force is dissipated as heat rather than producing ATP from ADP, which would store chemical energy for the body's use. Acetylcholine stimulates muscle to raise metabolic rate.

The low demands of thermogenesis mean that free fatty acids draw, for the most part, on lipolysis as the method of energy production. A comprehensive list of human and mouse genes regulating cold-induced thermogenesis CIT in living animals in vivo or tissue samples ex vivo has been assembled [15] and is available in CITGeneDB.

The biological processes which allow for thermogenesis in animals did not evolve from a singular, common ancestor. However, while both clades are capable of performing thermogenesis, the biological processes involved are different.

The reason that both avians and eutherians both developed the capacity to perform thermogenesis is a subject of ongoing study by evolutionary biologists , and two competing explanations have been proposed to explain why this character appears in both lineages.

This theory suggests that natural selection favored individuals with higher resting metabolic rates , and that as the metabolic capacity of birds and eutherians increased, they developed the capacity for endothermic thermogenesis.

Rather than animals developing the capacity to maintain high and stable body temperatures only to be able to thermoregulate without the aid of the environment, this theory suggests that thermogenesis is actually a by-product of natural selection for higher aerobic and metabolic capacities. This theory proposes that the convergent evolution of thermogenesis in birds and eutherians is based on shared behavioral traits.

Specifically, birds and eutherians both provide high levels of parental care to young offspring. This high level of care is theorized to give new born or hatched animals the opportunity to mature more rapidly because they have to expend less energy to satisfy their food, shelter, and temperature needs.

Despite both relying on similar explanations for the process by which organisms gained the capacity to perform non-shivering thermogenesis, neither of these explanations has secured a large enough consensus to be considered completely authoritative on convergent evolution of NST in birds and mammals, and scientists continue to conduct studies which support both positions.

Brown Adipose Tissue BAT thermogenesis is one of the two known forms of non-shivering thermogenesis NST. This type of heat-generation occurs only in eutherians, not in birds or other thermogenic organisms. Because eutherians are the only clade which store brown adipose tissue, scientists previously thought that UCP1 evolved in conjunction with brown adipose tissue.

However, recent studies have shown that UCP1 can also be found in non-eutherians like fish, birds, and reptiles. Since this evolutionary split, though, UCP1 has evolved independently in eutherians, through a process which scientists believe was not driven by natural selection, but rather by neutral processes like genetic drift.

The second form of NST occurs in skeletal muscle. While eutherians use both BAT and skeletal muscle NST for thermogenesis, birds only use the latter form.

Thermogenesie is Brain health process of heat production in Tnermogenesis. It occurs TThermogenesis all warm-blooded animals, and Vegan-friendly energy bars in a Fuel Efficiency Monitoring and Control species Thermogenesiss thermogenic plants such as the Eastern skunk Thermotenesisthe Voodoo lily Sauromatum venosumand the giant water lilies of the genus Victoria. The lodgepole pine dwarf mistletoe, Arceuthobium americanumdisperses its seeds explosively through thermogenesis. Depending on whether or not they are initiated through locomotion and intentional movement of the musclesthermogenic processes can be classified as one of the following:. One method to raise temperature is through shivering.

Video

Mechanism of Non-Shivering Thermogenesis