Postprandial Substrate Deposition in Human Forearm and Adipose Tissues in Vivo

1990 ◽  
Vol 79 (4) ◽  
pp. 339-348 ◽  
Author(s):  
S. W. Coppack ◽  
R. M. Fisher ◽  
G. F. Gibbons ◽  
S. M. Humphreys ◽  
M. J. McDonough ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Carbon Balance ◽  
Plasma Concentrations ◽  
Normal Subjects ◽  
Esterified Fatty Acids ◽  
Positive Balance ◽  
A Minor

1. Substrate movements in forearm muscle and subcutaneous adipose tissue were studied, by measurement of arteriovenous differences and blood flow, in seven normal subjects after an overnight fast and then for 6 h after ingestion of a mixed meal. Overall substrate balances were examined in terms of the flux of gram-atoms of carbon. 2. As found previously, the forearm was approximately in carbon balance (import equal to export) after the overnight fast, whereas adipose tissue was a net exporter of carbon, mainly in the form of non-esterified fatty acids. 3. After the meal, arterialized plasma concentrations of glucose and lactate rose sharply (peak at 60 min), whereas those of non-esterified fatty acids and glycerol fell (nadir at 60–120 min). Plasma triacylglycerol concentrations rose slowly to peak at 240 min; much of this rise was accounted for by a rise in the chylomicron fraction. 4. Both tissues took up glucose at an increased rate after the meal. Release of non-esterified fatty acids and glycerol from adipose tissue was suppressed. Clearance of triacylglycerol by both tissues increased after the meal, but was more marked in adipose tissue, where the fractional extraction of chylomicron-triacylglycerol reached 44% at 240 min. 5. The forearm rapidly became a considerable net importer of carbon, and remained so until 6 h after the meal when it was again in approximate carbon balance. Glucose uptake dominated the forearm carbon balance. Adipose tissue was a net importer of carbon from 30 min until 5 h after the meal and then reverted to net export. Clearance of triacylglycerol carbon made the largest contribution to this positive balance, but towards the end of the study this was increasingly counterbalanced by simultaneous non-esterified fatty acid release. 6. Skeletal muscle plays a major role, and adipose tissue a minor one, in the disposal of ingested carbohydrate; adipose tissue plays a major role and skeletal muscle a minor one in clearance of dietary-derived triacylglycerol. The role of adipose tissue lipoprotein lipase is not, however, simply the uptake of triacylglycerol for storage within the tissue; rather, it appears to play a central role in the distribution of dietary-derived lipid energy.

scholarly journals Insulin resistance of hind-limb tissues in vivo in lactating sheep

1990 ◽  
Vol 270 (3) ◽  
pp. 783-786 ◽  
Author(s):  
R G Vernon ◽  
A Faulkner ◽  
W W Hay ◽  
D T Calvert ◽  
D J Flint
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Mammary Gland ◽  
Hind Limb ◽  
Insulin Infusion ◽  
Plasma Concentrations ◽  
Plasma Insulin Concentration ◽  
Esterified Fatty Acids ◽  
Beta Hydroxybutyrate

1. The effects of varying the plasma insulin concentration by infusion while maintaining euglycaemia by infusion of glucose on nutrient arterio-venous differences across the hind-limb and mammary gland in lactating and non-lactating sheep were investigated. 2. Insulin infusion increased the glucose arterio-venous difference across the hind-limb; this effect of insulin was decreased by lactation, suggesting that lactation induces insulin resistance in skeletal muscle. 3. Lactation increased but insulin infusion decreased the plasma concentrations of acetate, beta-hydroxybutyrate and non-esterified fatty acids. 4. Insulin infusion decreased the arterio-venous differences of acetate and hydroxybutyrate across the hind-limb; this effect of insulin is probably indirect, resulting from the decrease in plasma concentrations of these metabolites. 5. Infusion of insulin had no effect on the glucose arterio-venous difference across the mammary gland, but did decrease the oxygen arterio-venous difference. 6. The results suggest that lactation results in insulin resistance in skeletal muscle, at least with respect to glucose utilization; this should facilitate the preferential utilization of glucose by the mammary gland.

scholarly journals Effects of an oral and intravenous fat load on adipose tissue and forearm lipid metabolism

1999 ◽  
Vol 276 (2) ◽  
pp. E241-E248 ◽  
Author(s):  
Kevin Evans ◽  
Mo L. Clark ◽  
Keith N. Frayn
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Hormone Sensitive Lipase ◽  
Nonesterified Fatty Acid ◽  
Subcutaneous Adipose

We have studied the fate of lipoprotein lipase (LPL)-derived fatty acids by measuring arteriovenous differences across subcutaneous adipose tissue and skeletal muscle in vivo. Six subjects were fasted overnight and were then given 40 g of triacylglycerol either orally or as an intravenous infusion over 4 h. Intracellular lipolysis (hormone-sensitive lipase action; HSL) was suppressed after both oral and intravenous fat loads ( P < 0.001). Insulin, a major regulator of HSL activity, showed little change after either oral or intravenous fat load, suggesting that suppression of HSL action occurred independently of insulin. The rate of action of LPL (measured as triacylglycerol extraction) increased with both oral and intravenous fat loads in adipose tissue ( P = 0.002) and skeletal muscle ( P = 0.001). There was increased escape of LPL-derived fatty acids into the circulation from adipose tissue, shown by lack of reesterification of fatty acids. There was no release into the circulation of LPL-derived fatty acids from skeletal muscle. These results suggest that insulin is not essential for HSL suppression or increased triacylglycerol clearance but is important in reesterification of fatty acids in adipose tissue but not uptake by skeletal muscle, thus affecting fatty acid partitioning between adipose tissue and the circulation, postprandial nonesterified fatty acid concentrations, and hepatic very low density lipoprotein secretion.

Metabolic responses to euglycaemic hyperinsulinaemia in lactating and non-lactating sheep in vivo

1990 ◽  
Vol 124 (1) ◽  
pp. 59-66 ◽  
Author(s):  
A. Faulkner ◽  
H. T. Pollock
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Insulin Infusion ◽  
Glucose Utilization ◽  
Plasma Concentrations ◽  
Hepatic Metabolism ◽  
Metabolic Responses ◽  
Plasma Metabolites

ABSTRACT Glucose utilization and production and changes in concentrations of plasma metabolites were studied in lactating and non-lactating sheep in response to three levels of insulin infusion whilst maintaining euglycaemia. Glucose utilization and production responded to insulin infusion similarly in both lactating and non-lactating ewes but, as circulating concentrations of insulin were lower in lactating animals, these parameters appeared more sensitive to plasma concentrations of insulin in lactating sheep. Changes in plasma concentrations of glycerol and free fatty acids during lactation indicated reduced sensitivity to insulin in adipose tissue and changes in plasma concentrations of amino acids were also less during lactation, suggesting reduced sensitivity of protein synthesis to insulin. Changes in plasma concentrations of urea and β-hydroxybutyrate during lactation were similar to those in non-lactating animals, indicating similar insulin sensitivity of hepatic metabolism. It is concluded that during lactation ovine adipose tissue and muscle are more resistant to increased concentrations of insulin but that the sensitivity of the sheep liver is unchanged or increased. The rate of removal of insulin from the circulation was higher in lactating animals. Journal of Endocrinology (1990) 124, 59–66

Effects of Insulin on Human Adipose Tissue Metabolism in Vivo

1989 ◽  
Vol 77 (6) ◽  
pp. 663-670 ◽  
Author(s):  
S. W. Coppack ◽  
K. N. Frayn ◽  
S. M. Humphreys ◽  
H. Dhar ◽  
T. D. R. Hockaday
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Oxygen Uptake ◽  
Carbon Balance ◽  
Insulin Infusion ◽  
Human Adipose Tissue ◽  
Metabolic Effects ◽  
Fasting State ◽  
Esterified Fatty Acids ◽  
Glucose Ingestion

1. The metabolic effects of insulin on human adipose tissue were studied by combining the euglycaemic clamp technique with measurement of arteriovenous differences across the subcutaneous adipose tissue of the anterior abdominal wall 2. Eight normal subjects were studied after an overnight fast, and for 120 min during infusion of insulin (mean arterialized plasma insulin 50–55 m-units/l) 3. During the insulin infusion, the arterialized and abdominal venous levels of both non-esterified fatty acids and glycerol fell, and the arteriovenous differences for the release of these substances narrowed. The fractional rate of re-esterification of fatty acids was around 20% in the fasting state and increased to almost 100% during hyper-insulinaemia 4. In the fasting state the uptake of glucose and 3-hydroxybutyrate by adipose tissue could account for only 20% of the oxygen uptake. During insulin infusion, adipose tissue glucose uptake increased and could account for more than 100% of oxygen uptake, implying storage of glucose 5. Net balances of different substrates across adipose tissue were examined by calculating fluxes in terms of μg-atoms of carbon. In the fasting state adipose tissue was in marked negative carbon balance (because of the export of non-esterified fatty acids); during insulin infusion it just reached ‘carbon balance’. These results were in contrast to those from a previous study of glucose ingestion, in which the adipose tissue showed marked positive carbon balance (net substrate deposition).

Effect of Propolis-Supplemented Diet on Body Composition and Endocrine Function of Adipose Tissue

2020 ◽  
Vol 19 (2) ◽  
pp. 217-221
Author(s):  
Maria Jesús Lisbona-González ◽  
Candela Reyes-Botella ◽  
Esther Muñoz-Soto ◽  
Maria Victoria Olmedo-Gaya, ◽  
Jorge Moreno-Fernandez ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Body Composition ◽  
Adipose Tissue ◽  
Endocrine Function ◽  
Control Group ◽  
Albino Rats ◽  
Standard Diet ◽  
Reduced Body ◽  
Esterified Fatty Acids ◽  
Wistar Albino Rats

Adipose tissue is an endocrine organ and has central role in interaction with other organs or tissues while propolis can induce lipolysis. Therefore, the aim of this study is to provide detailed information about adipose tissue homeostasis modifications and body composition during propolis supplement consumption. Twenty male Wistar albino rats (8 weeks) were divided into two groups of 10 animals each and fed for 90 days with two different types of diets: standard for the control group (diet C) and standard diet + 2% propolis (diet P). Thyroid hormones did not show differences, while ghrelin and adiponectin decreased in the group that was fed propolis. Insulin, leptin, and non-esterified fatty acids also increased along with reduced body weight and fat, in addition to increased lean mass when propolis was in the diet. We conclude that propolis could decrease ghrelin and adiponectin but increase non-esterified fatty acids and insulin secretion, which improves body composition.

Role of the AMP-activated protein kinase in regulating fatty acid metabolism during exerciseThis paper is one of a selection of papers published in this Special Issue, entitled 14th International Biochemistry of Exercise Conference – Muscles as Molecular and Metabolic Machines, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 34 (3) ◽  
pp. 315-322 ◽  
Author(s):  
Gregory R. Steinberg
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Moderate Intensity ◽  
Amp Activated Protein Kinase

During moderate-intensity exercise, fatty acids are the predominant substrate for working skeletal muscle. The release of fatty acids from adipose tissue stores, combined with the ability of skeletal muscle to actively fine tune the gradient between fatty acid and carbohydrate metabolism, depending on substrate availability and energetic demands, requires a coordinated system of metabolic control. Over the past decade, since the discovery that AMP-activated protein kinase (AMPK) was increased in accordance with exercise intensity, there has been significant interest in the proposed role of this ancient stress-sensing kinase as a critical integrative switch controlling metabolic responses during exercise. In this review, studies examining the role of AMPK as a regulator of fatty acid metabolism in both adipose tissue and skeletal muscle during exercise will be discussed. Exercise induces activation of AMPK in adipocytes and regulates triglyceride hydrolysis and esterfication through phosphorylation of hormone sensitive lipase (HSL) and glycerol-3-phosphate acyl-transferase, respectively. In skeletal muscle, exercise-induced activation of AMPK is associated with increases in fatty acid uptake, phosphorylation of HSL, and increased fatty acid oxidation, which is thought to occur via the acetyl-CoA carboxylase-malony-CoA-CPT-1 signalling axis. Despite the importance of AMPK in regulating fatty acid metabolism under resting conditions, recent evidence from transgenic models of AMPK deficiency suggest that alternative signalling pathways may also be important for the control of fatty acid metabolism during exercise.

PRESS echo time behavior of triglyceride resonances at 1.5T: Detecting ω-3 fatty acids in adipose tissue in vivo

2009 ◽  
Vol 201 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Jesper Lundbom ◽  
Sami Heikkinen ◽  
Barbara Fielding ◽  
Antti Hakkarainen ◽  
Marja-Riitta Taskinen ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Time Behavior ◽  
Echo Time

scholarly journals Analysis of free and protein-bound nitrotyrosine in human plasma by a gas chromatography/mass spectrometry method that avoids nitration artifacts

2000 ◽  
Vol 345 (3) ◽  
pp. 453-458 ◽  
Author(s):  
Matthew T. FROST ◽  
Barry HALLIWELL ◽  
Kevin P. MOORE
Keyword(s):  
Reactive Nitrogen Species ◽  
Plasma Proteins ◽  
Biological Fluids ◽  
Plasma Concentrations ◽  
Normal Subjects ◽  
Gas Chromatography Mass Spectrometry ◽  
Highly Sensitive ◽  
Acidic Conditions ◽  
First Time

Measurement of nitrotyrosine in biological fluids and tissues is increasingly being used to monitor the production of reactive nitrogen species in vivo. The detection of nitrotyrosine in vivo has been reported with the use of a variety of methods including immunoassay, HPLC and GLC/MS. The validity of HPLC and immunoassays have been questioned with regard to their selectivity and sensitivity limits. In principle, the measurement of nitrotyrosine by GLC/MS permits a highly specific, highly sensitive and fully quantitative assay. The nitration of tyrosine under acidic conditions in the presence of nitrite is well documented. Derivatization for the full quantification of nitrotyrosine by using GLC/MS can lead to the artifactual nitration of tyrosine if performed under acidic conditions in the presence of nitrite. We describe a novel alkaline method for the hydrolysis and derivatization of nitrotyrosine and tyrosine, and demonstrate its applicability to the measurement of plasma concentrations of both free and protein-bound nitrotyrosine and tyrosine. A detection limit of 1 pg for nitrotyrosine and 100 pg for tyrosine has been achieved. Our method allows, for the first time, the analysis of free and protein-bound nitrotyrosine and tyrosine in biological samples. The plasma concentrations (means±S.E.M.) of free tyrosine and nitrotyrosine in eight normal subjects were 12±0.6 μg/ml and 14±0.7 ng/ml respectively. Plasma proteins contained tyrosine and nitrotyrosine at 60.7±1.7 μg/mg and 2.7±0.4 ng/mg respectively.

scholarly journals The Effect of Combined Diet Containing n-3 Polyunsaturated Fatty Acids and Silymarin on Metabolic Syndrome in Rats

2019 ◽  
pp. S39-S50
Author(s):  
M. PORUBA ◽  
P. ANZENBACHER ◽  
Z. RACOVA ◽  
O. OLIYARNYK ◽  
M. HÜTTL ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Metabolic Syndrome ◽  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Metabolic Disorders ◽  
Male Rats ◽  
Lipid Homeostasis ◽  
Metabolic Disturbances ◽  
Serum Triglycerides ◽  
Esterified Fatty Acids

The risk of development of metabolic syndrome can be increased by hypertriglyceridemia. A search for effective therapy is a subject of considerable attention. Therefore, our hypothesis is that the fish oil (containing polyunsaturated fatty acids; n-3 PUFA) in a combination with silymarin can more effectively protect against hypertriglyceridemia-induced metabolic disturbances. The study was conducted using a unique non-obese strain of rats with hereditary hypertriglyceridemia an accepted model of metabolic syndrome. Adult male rats were treated with n-3 PUFA (300 mg/kg/day) without or with 1 % micronized silymarin in a diet for 4 weeks. The treatment with the diet containing n-3 PUFA and silymarin significantly reduced concentrations of serum triglycerides (-45 %), total cholesterol (-18 %), non-esterified fatty acids (-33 %), and ectopic lipid accumulation in skeletal muscle (-35 %) compared to controls. In addition, an increase in Abcg5 and Abcg8 mRNA expression (as genes affecting lipid homeostasis) as well as in protein content of ABCG5 (+78 %) and ABCG8 (+232 %) transporters have been determined in the liver of treated rats. Our findings suggest that this combined diet could be used in the prevention of hypertriglyceridemia-induced metabolic disorders.

scholarly journals Ultralong TE In Vivo 1 H MR Spectroscopy of Omega‐3 Fatty Acids in Subcutaneous Adipose Tissue at 7 T

2018 ◽  
Vol 50 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Martin Gajdošík ◽  
Lukas Hingerl ◽  
Antonín Škoch ◽  
Angelika Freudenthaler ◽  
Patrik Krumpolec ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Mr Spectroscopy ◽  
Subcutaneous Adipose Tissue ◽  
Omega 3 Fatty Acids ◽  
Omega 3 ◽  
Subcutaneous Adipose
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