Fate of fatty acids at rest and during exercise: regulatory mechanisms

The human body requires energy to function. Adenosine triphosphate (ATP) is the cellular currency for energy-requiring processes including mechanical work (i.e., exercise). ATP used by the cells is ultimately derived from the catabolism of energy substrate molecules—carbohydrates, fat, and protein. In prolonged moderate to high-intensity exercise, there is a delicate interplay between carbohydrate and fat metabolism, and this bioenergetic process is tightly regulated by numerous physiological, nutritional, and environmental factors such as exercise intensity and duration, body mass and feeding state. Carbohydrate metabolism is of critical importance during prolonged endurance-type exercise, reflecting the physiological need to regulate glucose homeostasis, assuring optimal glycogen storage, proper muscle fuelling, and delaying the onset of fatigue. Fat metabolism represents a sustainable source of energy to meet energy demands and preserve the ‘limited’ carbohydrate stores. Coordinated neural, hormonal and circulatory events occur during prolonged endurance-type exercise, facilitating the delivery of fatty acids from adipose tissue to the working muscle for oxidation. However, with increasing exercise intensity, fat oxidation declines and is unable to supply ATP at the rate of the exercise demand. Protein is considered a subsidiary source of energy supporting carbohydrates and fat metabolism, contributing to approximately 10% of total ATP turnover during prolonged endurance-type exercise. In this review we present an overview of substrate metabolism during prolonged endurance-type exercise and the regulatory mechanisms involved in ATP turnover to meet the energetic demands of exercise.

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Changes in plasma glucose, FFA, corticosterone, and thyroxine in He-O2-induced hypothermia

Journal of Applied Physiology ◽

10.1152/jappl.1977.42.5.694 ◽

1977 ◽

Vol 42 (5) ◽

pp. 694-698 ◽

Cited By ~ 10

Author(s):

L. C. Wang ◽

R. E. Peter

Keyword(s):

Fatty Acids ◽

Body Temperature ◽

Ambient Temperature ◽

Plasma Glucose ◽

Spontaneous Recovery ◽

Male Rats ◽

Regulatory Mechanisms ◽

Induced Hypothermia ◽

Blood Samples ◽

Metabolic Substrates

Unanesthetized, male rats were exposed to normal air (NA), or NA and a 4 h-exposure of He-O2 (79% helium, 21% oxygen) at ambient temperature (Ta) of 22 or - 10 degrees C. Blood samples from each individual were taken from a chronically implanted carotid cannula at 1) preexposure, 2) during exposure, 3) 2.5 h after exposure, and 4) 19–20 h after exposure. Exposure to He-O2 at 22 degrees C caused an increase in plasma free fatty acids (FFA) and corticosterone of 45% and 49%, respectively, with little change in plasma glucose and thyroxine. Exposure to He-O2 at 10 degrees C for 3 h invariably induced hypothermia with body temperature (Tb) decreased to 23.7 +- 0.5 degrees C (N = 10). During hypothermia, plasma glucose, FFA, and corticosterone were significantly higher (P LESS THAN 0.05) than those at preexposure and those after exposure to NA at -10 degrees C. During spontaneous recovery from hypothermia, at Ta = 19 degrees C and NA, glucose, corticosterone, and thyroxine returned to normal, but FFA remained significantly higher than at preexposure. The ability of animals to rewarm spontaneously from hypothermia and the quick return of metabolic substrates and hormones to normal after rewarming indicates the preservation of regulatory mechanisms for metabolism at depressed Tb when hypothermia is induced by He-O2 and cold.

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A physiological perspective on targets of nitration in NO-based signaling networks in plants

Journal of Experimental Botany ◽

10.1093/jxb/erz300 ◽

2019 ◽

Vol 70 (17) ◽

pp. 4379-4389 ◽

Cited By ~ 10

Author(s):

Magdalena Arasimowicz-Jelonek ◽

Jolanta Floryszak-Wieczorek

Keyword(s):

Fatty Acids ◽

Cellular Responses ◽

Regulatory Mechanisms ◽

Signaling Networks ◽

Tyrosine Nitration ◽

Biological Processes ◽

Modeling Tools ◽

Intracellular Traffic ◽

Dna And Rna ◽

Fine Tune

Abstract Although peroxynitrite (ONOO−) has been well documented as a nitrating cognate of nitric oxide (NO) in plant cells, modifications of proteins, fatty acids, and nucleotides by nitration are relatively under-explored topics in plant NO research. As a result, they are seen mainly as hallmarks of redox processes or as markers of nitro-oxidative stress under unfavorable conditions, similar to those observed in human and other animal systems. Protein tyrosine nitration is the best-known nitrative modification in the plant system and can be promoted by the action of both ONOO− and related NO-derived oxidants within the cell environment. Recent progress in ‘omics’ and modeling tools have provided novel biochemical insights into the physiological and pathophysiological fate of nitrated proteins. The nitration process can be specifically involved in various cell regulatory mechanisms that control redox signaling via nitrated cGMP or nitrated fatty acids. In addition, there is evidence to suggest that nitrative modifications of nucleotides embedded in DNA and RNA can be considered as smart switches of gene expression that fine-tune adaptive cellular responses to stress. This review highlights recent advances in our understanding of the potential implications of biotargets in the regulation of intracellular traffic and plant biological processes.

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Oleic and palmitic acids induce hepatic angiopoietin-like 4 expression predominantly via PPAR-γ in Larimichthys crocea

British Journal Of Nutrition ◽

10.1017/s000711452100386x ◽

2021 ◽

pp. 1-27

Author(s):

Xiaojun Xiang ◽

Shangzhe Han ◽

Dan Xu ◽

Qiuchi Chen ◽

Renlei Ji ◽

...

Keyword(s):

Fatty Acids ◽

Mrna Expression ◽

Regulatory Mechanisms ◽

Large Yellow Croaker ◽

Peroxisome Proliferator ◽

Larimichthys Crocea ◽

Peroxisome Proliferator Activated Receptor ◽

Triacylglycerol Metabolism ◽

Palmitic Acids

Abstract Angiopoietin-like 4 (ANGPTL4) is a potent regulator of triacylglycerol metabolism but knowledge of the mechanisms underlying ANGPTL4 transcription in response to fatty acids is still limited in teleost. In this study, we explored the molecular characterization of ANGPTL4 and regulatory mechanisms of ANGPTL4 in response to fatty acids in large yellow croaker (Larimichthys crocea). Here, croaker angptl4 contained a 1416 bp open reading frame encoding a protein of 471 amino acids with highly conserved 12-amino acid consensus motif. Angptl4 was widely expressed in croaker, with the highest expression in the liver. In vitro, oleic and palmitic acids (OA and PA) treatments strongly increased angptl4 mRNA expression in croaker hepatocytes. Moreover, angptl4 expression was positively regulated by peroxisome proliferator-activated receptor family (PPAR-α, β and γ) and expression of pparγ was also significantly increased in response to OA and PA. Moreover, inhibition of PPARγ abrogated OA or PA-induced angptl4 mRNA expression. Beyond that, PA might increase angptl4 expression partly via the insulin signaling. Overall, the expression of ANGPTL4 is strongly upregulated by OA and PA via PPARγ in the liver of croaker, which contributes to improve the understanding of the regulatory mechanisms of ANGPTL4 in fish.

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Novel Lipidomes Profile and Clinical Phenotype Identified in Pneumoconiosis Patients

10.21203/rs.3.rs-814567/v1 ◽

2021 ◽

Author(s):

Liyong Shi ◽

Xiaofang Dai ◽

Furong Yan ◽

Yujun Lin ◽

Lianshun Lin ◽

...

Keyword(s):

Fatty Acids ◽

Lipid Metabolism ◽

Poor Prognosis ◽

Lung Diseases ◽

Clinical Phenotype ◽

Regulatory Mechanisms ◽

The World ◽

Occupational Lung Diseases ◽

Clinically Significant ◽

Circulating Levels

Abstract Pneumoconiosis is a group of occupational lung diseases caused by inhalation of particles of coal, asbestos, silica, or similar substances, leading to fibrosis and loss of lung function. It is the most serious and common occupational disease in the world with an increased incidence but poor prognosis. To further investigate the regulatory mechanisms of lipidomic profiles in pneumoconiosis, we measured plasma lipidomic profiles between pneumoconiosis patients and health. Compared with healthy people, it showed that circulating levels of phosphatidylethanolamine (PE) and free fatty acids (FFA) significantly increased while phosphatidylcholines (PC) and lysophosphatidylcholines (lyso PC) decreased in patients with pneumoconiosis. Clinical trans-omics analyses demonstrated that phenomes in pneumoconiosis connections with multiple lipids. Our data suggested that trans-omic analysis between clinical phenomes and lipidomes might have the potential to uncover the heterogeneity of lipid metabolism of pneumoconiosis patients and to screen out clinically significant phenome-based lipid panels.

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Effects of selective hepatic vagotomy on running endurance in rats

Journal of Applied Physiology ◽

10.1152/jappl.1990.69.6.2197 ◽

1990 ◽

Vol 69 (6) ◽

pp. 2197-2201 ◽

Cited By ~ 3

Author(s):

B. Doiron ◽

S. Cardin ◽

G. R. Brisson ◽

J. M. Lavoie

Keyword(s):

Fatty Acids ◽

Plasma Glucose ◽

Functional Significance ◽

Food Restriction ◽

Metabolic Regulation ◽

Regulatory Mechanisms ◽

Hepatic Glycogen ◽

Time To Exhaustion ◽

Endurance Time ◽

Metabolic Adaptations

The liver, through the afferent ways of the vagus hepatic nerve, may influence metabolic adaptations during exercise. This study assesses the functional significance of this hepatic innervation by determining the effect of a selective hepatic vagotomy (HV) on running endurance time during submaximal activity in rats subjected to an overnight 50% food restriction. The time to exhaustion was similar for the groups of HV and sham-operated (SHM) rats [66 +/- 15 vs. 64 +/- 21 (SD) min]. The HV group was associated with higher resting levels (P less than 0.05) of hepatic glycogen and plasma glucose. No significant differences were observed between HV and SHM rats at rest and after exercise for muscle glycogen, free fatty acids, insulin, glucagon, and lactate concentrations. These data indicate that if hepatic glucoreceptors do exist and contribute to the metabolic regulation of exercise, their functional significance is secondary to more important regulatory mechanisms.

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