scholarly journals Tracing the fate of dietary fatty acids: metabolic studies of postprandial lipaemia in human subjects

2011 ◽  
Vol 70 (3) ◽  
pp. 342-350 ◽  
Author(s):  
Barbara Fielding
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Stable Isotope ◽  
Dietary Fat ◽  
Western Society ◽  
Plasma Nefa ◽  
Stable Isotope Tracers ◽  
Isotope Tracers

Most postprandial studies have investigated the response of a single meal, yet the ingestion of sequential meals is more typical in a Western society. The aim of this review is to explain how natural and stable isotope tracers of fatty acids have been used to investigate the metabolism of dietary fat after single and multiple meals, with a focus on in vivo measurements of adipose tissue metabolism. When stable isotope tracers are combined with arteriovenous difference measurements, very specific measurements of metabolic flux across tissues can be made. We have found that adipose tissue is a net importer of dietary fat for 5 h following a single test meal and for most of the day during a typical three-meal eating pattern. When dietary fat is cleared from plasma, some fatty acids ‘spillover’ into the plasma and contribute up to 50% of postprandial plasma NEFA concentrations. Therefore, plasma NEFA concentrations after a meal reflect the balance between intracellular and extracellular lipolysis in adipose tissue. This balance is altered after the acute ingestion of fructose. The enzyme lipoprotein lipase is a key modulator of fatty acid flux in adipose tissue and its rate of action is severely diminished in obese men. In conclusion, in vivo studies of human metabolism can quantify the way that adipose tissue fatty acid trafficking modulates plasma lipid concentrations. This has implications for the flux of fatty acids to tissues that are susceptible to ectopic fat deposition such as the liver and muscle.

scholarly journals INFLUENCE OF DIETARY FAT LEVEL ON GROWTH AND BODY COMPOSITION OF THE NEONATAL PIG

1985 ◽  
Vol 65 (1) ◽  
pp. 175-184 ◽  
Author(s):  
N. K. SARKAR ◽  
J. K. G. KRAMER ◽  
J. I. ELLIOT ◽  
M. S. WOLYNETZ
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Dietary Fat ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Essential Fatty Acids ◽  
Fat Content ◽  
Acid Biosynthesis

Four Yorkshire piglets, from each of 18 litters, were randomly allotted within litters, to four treatment groups 12 h after birth. Group 1 (Control) continued to be suckled by sows; the remaining piglets were reared artificially on a semi-synthetic liquid diet containing either 25% soybean oil (SBO) (group 2) or 3% SBO plus 22% lactose (groups 3 and 4). At 7, 14 and 21 days of age, 24 pigs from six litters were killed. Piglets on the 25% SBO diet grew faster (P < 0.05) than those on the 3% SBO diet while the growth rate of the suckled piglets tended to be between the growth rates of those on the two SBO diets. Body fat content increased with the fat content in the diet and with age. The protein:fat ratio was greatest in the piglets on the 3% SBO diet and least in the suckled piglets. The fatty acid composition of backfat changed, primarily during the first week of life, towards that of the dietary fat. This was evident even in piglets on the low fat-high carbohydrate (3% SBO) diet. The composition of the fat deposited in piglets on the 3% SBO group indicated preferential utilization of essential fatty acids and little de novo synthesis of fatty acids. The amount and type of fat deposited by piglets fed the 3% SBO diet, together with preliminary evidence of low incorporation of radioactivity from (U14C) glucose with adipose tissue fatty acids in vivo, suggest that the de novo fatty acid biosynthesis in adipose tissue of piglets is not as high as previously reported (Mersmann et al. 1973). Key words: Neonatal pigs, fat deposition, fatty acid biosynthesis.

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 Metabolism and secretory function of white adipose tissue: effect of dietary fat

2009 ◽  
Vol 81 (3) ◽  
pp. 453-466 ◽  
Author(s):  
Cláudia M. Oller do Nascimento ◽  
Eliane B. Ribeiro ◽  
Lila M. Oyama
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
White Adipose Tissue ◽  
Dietary Fat ◽  
Dietary Fatty Acids ◽  
Secretory Function ◽  
High Fat ◽  
Adipose Tissue Metabolism ◽  
Tissue Metabolism

Approximately 40% of the total energy consumed by western populations is represented by lipids, most of them being ingested as triacylglycerols and phospholipids. The focus of this review is to analyze the effect of the type of dietary fat on white adipose tissue metabolism and secretory function, particularly on haptoglobin, TNF-α, plasminogen activator inhibitor-1 and adiponectin secretion. Previous studies have demonstrated that the duration of the exposure to the high-fat feeding, amount of fatty acid present in the diet and the type of fatty acid may or may not have a significant effect on adipose tissue metabolism. However, the long-term or short-term high fat diets, especially rich in saturated fatty acids, probably by activation of toll-like receptors, stimulated the expression of proinflammatory adipokines and inhibited adiponectin expression. Further studies are needed to investigate the cellular mechanisms by which dietary fatty acids affect white adipose tissue metabolism and secretory functions.

The 1990 Borden Award Lecture Dietary regulation of fatty acid and triglyceride metabolism

1991 ◽  
Vol 69 (11) ◽  
pp. 1637-1647 ◽  
Author(s):  
Gene R. Herzberg
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Lipoprotein Lipase ◽  
Fatty Acid Synthesis ◽  
Dietary Fat ◽  
Acid Synthesis ◽  
Fish Oils ◽  
Dietary Fish

The level of circulating triacylglycerols is determined by the balance between their delivery into the plasma and their removal from it. Plasma triacylglycerols are derived either from dietary fat as chylomicrons or from endogenous hepatic synthesis as very low density lipoproteins. Their removal occurs through the action of lipoprotein lipase after which the fatty acids are either stored in adipose tissue or oxidized, primarily in skeletal muscle and heart. The composition of the diet has been shown to influence many of these processes. Hepatic fatty acid synthesis and triacylglycerol secretion are affected by the quantity and composition of dietary fat, carbohydrate, and protein. Polyunsaturated but not saturated fats reduce hepatic fatty acid synthesis by decreasing the amount of the lipogenic enzymes needed for de novo fatty acid synthesis. Dietary fish oils are particularly effective at reducing both fatty acid synthesis and triacylglycerol secretion and as a result are hypotriacylglycerolemic, particularly in hypertriacylglycerolemic individuals. In addition, dietary fish oils can increase the oxidation of fatty acids and lead to increased activity of lipoprotein lipase in skeletal muscle and heart. It appears that the hypotriacylglycerolemic effect of dietary fish oils is mediated by effects on both synthesis and removal of circulating triacylglycerols.Key words: lipid, fish oil, fructose, liver, adipose tissue, oxidation.

Uptake of glucose and release of fatty acids and glycerol by rat brown adipose tissue in vivo

1986 ◽  
Vol 64 (5) ◽  
pp. 609-614 ◽  
Author(s):  
Stephanie W. Y. Ma ◽  
David O. Foster
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Tissue Blood Flow ◽  
Glycerol Release ◽  
Maximal Stimulation ◽  
Brown Adipose ◽  
Lactate And Pyruvate

The net in vivo uptake or release of free fatty acids glycerol, glucose, lactate, and pyruvate by the interscapular brown adipose tissue (IBAT) of barbital-anesthetized, cold-acclimated rats was determined from measurements of plasma arteriovenous concentration differences across IBAT and tissue blood flow. Measurements were made without stimulation of the tissue and also during submaximal and maximal stimulation by infused noradrenaline (NA), the physiological activator of BAT thermogenesis. There was no appreciable uptake of glucose or release of fatty acids and glycerol by the nonstimulated tissue. At both levels of stimulation there was significant uptake of glucose (1.7 and 2.0 μmol/min) and release of glycerol (0.9 and 1.2 μmol/min), but only at maximal stimulation was there significant release of fatty acids (1.9 μmol/min). Release of lactate and pyruvate accounted for 33% of the glucose taken up at submaximal stimulation and 88% at maximal stimulation. By calculation, the remainder of the glucose taken up was sufficient to have fueled about 12% of the thermogenesis at submaximal stimulation, but only about 2% at maximal stimulation. As estimated from the rate of glycerol release, the rate of triglyceride hydrolysis was sufficient at submaximal stimulation to fuel IBAT thermogenesis entirely with the resulting fatty acids, but it was not sufficient to do so at maximal stimulation when some of the fatty acid was exported. It is suggested that at maximal NA-induced thermogenesis a portion of lipolysis proceeded only to the level of mono- and di-glycerides with the result that glycerol release did not fully reflect the rate of fatty acid formation. Both in absolute terms and in relation to the export of glycerol the in vivo export of fatty acids from the adipocytes of IBAT was much less than is observed with brown adipocytes in vitro.

THE STIMULATING EFFECTS OF ADRENALINE AND ANTERIOR PITUITARY HORMONES ON THE RELEASE OF FREE FATTY ACIDS FROM ADIPOSE TISSUE

1962 ◽  
Vol 25 (2) ◽  
pp. 189-198 ◽  
Author(s):  
R. M. BUCKLE
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Pituitary Hormones ◽  
Thyroid Stimulating Hormone ◽  
Adrenocorticotrophic Hormone ◽  
Fat Pads

SUMMARY The quantity of free fatty acids (FFA) released from rat epididymal fat pads in vitro and their concentration within the tissue were determined. The addition of adrenaline, adrenocorticotrophic hormone (ACTH), thyroid stimulating hormone (TSH) and growth hormone (GH) each increased the release of FFA, and their respective minimum effective concentrations were 0·125, 0·004, 0·5 and 1·25 μg./ml. of medium. In every case, the increased release of FFA was associated with a rise in the quantity present within the pads, and the amount released closely paralleled their concentration within the tissue. It is suggested that the stimulatory effect of all four hormones on the release of FFA from adipose tissue is largely a manifestation of their activity of increasing the concentration of FFA within the cells, and this they do by facilitating the net conversion of storage triglyceride to fatty acid. The significance of the relative activities of the hormones in vitro is discussed and compared with their fatty acid mobilizing effects in vivo.

Hormone-sensitive lipase-independent adipocyte lipolysis during β-adrenergic stimulation, fasting, and dietary fat loading

2004 ◽  
Vol 287 (2) ◽  
pp. E282-E288 ◽  
Author(s):  
Mélanie Fortier ◽  
Shu Pei Wang ◽  
Pascale Mauriège ◽  
Meriem Semache ◽  
Léandra Mfuma ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
White Adipose Tissue ◽  
Dietary Fat ◽  
Intraperitoneal Administration ◽  
Hormone Sensitive Lipase ◽  
Adrenergic Stimulation ◽  
Hormone Sensitive ◽  
Isolated Adipocytes

In white adipose tissue, lipolysis can occur by hormone-sensitive lipase (HSL)-dependent or HSL-independent pathways. To study HSL-independent lipolysis, we placed HSL-deficient mice in conditions of increased fatty acid flux: β-adrenergic stimulation, fasting, and dietary fat loading. Intraperitoneal administration of the β3-adrenergic agonist CL-316243 caused a greater increase in nonesterified fatty acid level in controls (0.33 ± 0.05 mmol/l) than in HSL−/− mice (0.12 ± 0.01 mmol/l, P < 0.01). Similarly, in isolated adipocytes, lipolytic response to CL-316243 was greatly reduced in HSL−/− mice compared with controls. Fasting for ≤48 h produced normal mobilization and oxidation of fatty acids in HSL−/− mice, as judged by similar values of respiratory quotient and oxygen consumption as in HSL+/+ controls. In isolated adipocytes, lipolysis in the absence of β-adrenergic stimulation was 1.9-fold greater in HSL−/− than in HSL+/+ cells ( P < 0.05), increasing to 6.5-fold after fasting ( P < 0.01). After 6 wk of a fat-rich diet containing 31.5% of energy as lipid, weight gain of HSL−/− mice was 4.4-fold less than in HSL+/+ mice ( P < 0.01), and total abdominal fat mass was 5.2-fold lower in HSL−/− than in HSL+/+ mice ( P < 0.01). In white adipose tissue, HSL is essential for normal acute β-adrenergic-stimulated lipolysis and permits normal triglyceride storage capacity in response to dietary fat loading. However, HSL-independent lipolysis can markedly increase during fasting, both in isolated adipocytes and in intact mice, and can mediate a normal flux of fatty acids during fasting.

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.

scholarly journals Polyunsaturated fatty acid-rich diets: effect on adipose tissue metabolism in rats

2001 ◽  
Vol 86 (3) ◽  
pp. 371-377 ◽  
Author(s):  
M. H. G. Gaíva ◽  
R. C. Couto ◽  
L. M. Oyama ◽  
G. E. C. Couto ◽  
V. L. F. Silveria ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Body Weight ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Malic Enzyme ◽  
Atp Citrate Lyase ◽  
Adipose Tissue Metabolism ◽  
Tissue Metabolism ◽  
Citrate Lyase

The aim of the present study was to evaluate the effect of diets rich in n-6 and n-3 fatty acids on adipose tissue metabolism. Starting at weaning, male Wistar rats were fed ad libitum, for 8 weeks with one of the following diets: C, rat chow; S, rat chow containing 15 % (w/w) soyabean oil; F, rat chow containing 15 % (w/w) fish oil; SF, rat chow containing 15 % (w/w) soyabean and fish oil (5:1, w/w). Casein was added to the fat diets to achieve the same 20 % (w/w) protein content as in the control chow. Food intake and body weight were measured weekly. The rats were killed by decapitation and the retroperitoneal (RET) and epididymal (EPI) white adipose tissues were removed and weighed. Tissue lipid and protein content, in vivo lipogenesis rate, uptake of diet-derived lipids, in vitro lipolytic rate, adipocyte area, lipoprotein lipase, ATP citrate lyase, and malic enzyme activities were evaluated. Carcass lipid and protein contents were also measured. Energy intake was reduced while carcass lipid content was increased in the three fat-fed groups. However, carcass protein and body weight gains were elevated only with diets F and SF. Lipolysis rate was diminished by diets F and SF, while the uptake of diet-derived lipids was elevated by the diet S in both RET and EPI tissues. These metabolic alterations may have contributed to the increase in in vivo lipogenesis rate in the presence of decreased ATP citrate lyase and malic enzyme activities induced by the three lipid diets. These results indicate that enrichment of the diet with polyunsaturated fatty acids causes changes in adipose tissue metabolism that favour fat deposition. Different metabolic pathways were preferentially affected by each type of fatty acid used.

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