A novel function of cockroach ( Periplaneta americana) hypertrehalosemic hormone: translocation of lipid from hemolymph to fat body

This work analyzed the process of lipid storage in fat body of larval Manduca sexta, focusing on the role of lipid transfer particle (LTP). Incubation of fat bodies with [(3)H]diacylglycerol-labeled lipophorin resulted in a significant accumulation of diacylglycerol (DAG) and triacylglycerol (TAG) in the tissue. Transfer of DAG to fat body and its storage as TAG was significantly inhibited (60%) by preincubating the tissue with anti-LTP antibody. Lipid transfer was restored to control values by adding LTP to fat body. Incubation of fat body with dual-labeled DAG lipophorin or its treatment with ammonium chloride showed that neither a membrane-bound lipoprotein lipase nor lipophorin endocytosis is a relevant pathway to transfer or to storage lipids into fat body, respectively. Treatment of fat body with suramin caused a 50% inhibition in [(3)H]DAG transfer from lipophorin. Treatment of [(3)H]DAG-labeled fat body with lipase significantly reduced the amount of [(3)H]DAG associated with the tissue, suggesting that the lipid is still on the external surface of the membrane. Whether this lipid represents irreversibly adsorbed lipophorin or a DAG lipase-sensitive pool is unknown. Nevertheless, these results indicate that the main pathway for DAG transfer from lipophorin to fat body is via LTP and receptor-mediated processes.

We hypothesized that the polyunsaturated fatty acids of the butterfly were probably derived from the diet and that there might be a great loss of body fat during metamorphosis. To substantiate these hypotheses, we analyzed the fatty acid composition and content of the diet, the larva, and the butterfly Morpho peleides. Both the diet and the tissues of the larva and butterfly had a high concentration of polyunsaturated fatty acids. In the diet, linolenic acid accounted for 19% and linoleic acid for 8% of total fatty acids. In the larva, almost 60% of the total fatty acids were polyunsaturated: linolenic acid predominated at 42% of total fatty acids, and linoleic acid was at 17%. In the butterfly, linolenic acid represented 36% and linoleic acid represented 11% of total fatty acids. The larva had a much higher total fatty acid content than the butterfly (20.2 vs. 6.9 mg). Our data indicate that the transformation from larva to butterfly during metamorphosis drastically decreased the total fatty acid content. There was bioenhancement of polyunsaturated fatty acids from the diet to the larva and butterfly. This polyunsaturation of membranes may have functional importance in providing membrane fluidity useful in flight.

Evidence that free fatty acids in trophocytes of Periplaneta americana fat body may be regulated by the activity of phospholipase A 2 and cyclooxygenase

Association between increased concentrations of free thyroxine and unsaturated free fatty acids in non-thyroidal illnesses: Role of albumin

Influence of long-chain free fatty acids on the binding of warfarin to bovine serum albumin

Skeletal muscles contain a fraction of free (unesterified) fatty acids. This fraction is very small, but important since it contributes to the creation of the plasma-myocyte free fatty acid concentration gradient. Maintenance of this gradient is necessary for blood-borne fatty acids to be transported into the cell. There are no data on the regulation of the content and composition of the free fatty acid fraction in the cell. The aim of the present study was to examine the effect of an elevation and a reduction in the plasma-borne free fatty acid concentration on the content and composition of the free fatty acid fraction in different skeletal muscle types. The experiments were carried out on male Wistar rats with 280 - 310 g body weight. They were divided into four groups - 1, control; 2, exercised 3 h on a treadmill moving with a speed of 1,200 m/h and set at + 10 degrees incline; 3, treated with heparin; and 4, treated with nicotinic acid. Samples of the soleus as well as the red and white sections of the gastrocnemius muscles were taken. These muscles are composed mostly of slow-twitch oxidative, fast-twitch oxidative-glycolytic and fast-twitch glycolytic fibres, respectively. Lipids were extracted from the muscle samples and from the blood; the free fatty acid fraction was isolated by means of thin-layer chromatography. The individual free fatty acids were identified and quantified using gas-liquid chromatography. The plasma concentration of free fatty acids was as follows: control group, 236.1 +/- 32.9; after exercise, 407.4 +/- 117.5; after heparin, 400.8 +/- 36.8; and after nicotinic acid, 102.5 +/- 26.1 micromol/l (p < 0.01 vs. control values in each case). The total content of the free fatty acid fraction in the control group was as follows: white gastrocnemius, 27.6 +/- 7.3; red gastrocnemius, 52.2 +/- 13.9; soleus, 72.3 +/- 10.2 nmol/g. Elevation in plasma free acid concentration during exercise increased the total content of free fatty acids in the white gastrocnemius (38.7 +/- 13.9) and in the soleus (103.4 +/- 15.9 nmol/g; rest-exercise: p < 0.05 and p < 0.01, respectively), but had no effect in the red gastrocnemius. Neither elevation in the plasma free fatty acid concentration with heparin nor reduction with nicotinic acid affected the total content of the free fatty acid fraction in the muscles examined. The ratio of plasma concentration of individual acid to muscle concentration for the same acid varied greatly, depending on acid, muscle type and experimental group. The ratio was positive (above unity) for each acid almost in all cases with the exception of certain acids in the nicotinic acid-treated group where it was below unity. We conclude that the skeletal myocytes maintain a stable level of free fatty acid fraction in the wide range of plasma free fatty acid concentrations.

1. Livers from normal and alloxan diabetic rats were perfused in vitro with a medium in which the concentration of free fatty acid was maintained at relatively constant levels by the infusion of a complex of oleic acid and bovine serum albumin. Concentrations of free fatty acid up to 3.5 mm in the cell-free perfusate were attained. 2. Throughout the range of concentration of free fatty acid which might be expected in the blood under normal and pathological conditions in vivo, the uptake of free fatty acid by the liver in vitro was proportional to the concentration in the medium; rates of uptake of free fatty acid approached saturation only at concentrations of free fatty acid in excess of those encountered in vivo. 3. The accumulation of triglyceride in livers from normal and most probably also in livers from alloxan diabetic rats was proportional to the concentration of free fatty acid in the medium. In contrast to triglyceride, the concentrations of total phospholipid, cholesterol, cholesteryl esters, and free fatty acid in the livers from normal and alloxan diabetic animals was independent of the concentration of free fatty acid in the perfusate. 4. Ketogenesis by livers from normal rats was dependent on the concentration of oleate in the medium; the maximal rates of production of ketone bodies were observed at 1.7 mm oleate. The rate of ketogenesis by livers from normal rats never equaled that by livers from alloxan diabetic animals, regardless of the concentration of free fatty acid in the medium. Although ketogenesis by livers from diabetic rats was responsive to the presence of oleate in the medium, similar and rapid rates of production of ketone bodies were observed over the entire range of concentration of free fatty acid. When livers from normal animals were exposed to high concentrations of oleate and the free fatty acid was withdrawn subsequently, the rates of ketogenesis diminished rapidly even though the concentration of triglyceride was elevated in the liver; glucagon, infused for 3 hours after oleate had been discontinued, could sustain the high rate of ketogenesis only for the short period during which free fatty acid remained in the medium. These observations force us to consider that, unlike free fatty acid, triglyceride fatty acid which accumulates in the livers of normal, fed rats is oxidized slowly, and that glucagon may not exert a major ketogenic action by stimulation of a hepatic triglyceride lipase.

The goal of this study was to develop a rapid and sensitive method to simultaneously determine the free and esterified fatty acid content of soybean oil (SBO) in the same GC-FID run. Using base catalysis with sodium methoxide in methanol, we were able to selectively derivatize the esterified fatty acids to methyl esters and then separate and measure both the free and esterified fatty acids using a free fatty acid phase (FFAP) column. This method was compared to titration, a traditional method of determining acidity in food fats. Using base catalysis, the esterified fatty acid content of the soybean oil was found to be similar to published values. Interestingly, there were similar proportions of free palmitate, stearate, oleate, linoleate, and linolenate at trace levels in the SBO. To compare the methods, soybean oil was spiked with free linoleate from 0.04% to 5%. Using titration, the standard curves indicated that the free fatty acid content over a series of samples, measured as oleic acid, had a r2 value of 0.999. Standard curves from gas chromatography showed an r2 value of 0.998 of linoleic acid added in the sample. However, the base catalysis GC method was inaccurate below 0.5% added linoleic acid due to incomplete transesterification. Using thin layer chromatography, it was established that there were residual mono- and diglycerides in the sample. This was not the case when potassium hydroxide in methanol was used. Once the detection limit of free fatty acids is established, this method would be valuable for rapid screening of food fats for free fatty acids.

We assessed the ability of endothelial lipase (EL) to hydrolyze the sn-1 and sn-2 fatty acids (FAs) from HDL phosphatidylcholine. For this purpose, reconstituted discoidal HDLs (rHDLs) that contained free cholesterol, apolipoprotein A-I, and either 1-palmitoyl-2-oleoylphosphatidylcholine, 1-palmitoyl-2-linoleoylphosphatidylcholine, or 1-palmitoyl-2-arachidonylphosphatidylcholine were incubated with EL- and control (LacZ)-conditioned media. Gas chromatography analysis of the reaction mixtures revealed that both the sn-1 (16:0) and sn-2 (18:1, 18:2, and 20:4) FAs were liberated by EL. The higher rate of sn-1 FA cleavage compared with sn-2 FA release generated corresponding sn-2 acyl lyso-species as determined by MS analysis. EL failed to release sn-2 FA from rHDLs containing 1-O-1'-hexadecenyl-2-arachidonoylphosphatidylcholine, whose sn-1 position contained a nonhydrolyzable alkyl ether linkage. The lack of phospholipase A(2) activity of EL and its ability to liberate [(14)C]FA from [(14)C]lysophosphatidylcholine (lyso-PC) led us to conclude that EL-mediated deacylation of phosphatidylcholine (PC) is initiated at the sn-1 position, followed by the release of the remaining FA from the lyso-PC intermediate. Thin-layer chromatography analysis of cellular lipids obtained from EL-overexpressing cells revealed a pronounced accumulation of [(14)C]phospholipid and [(14)C]triglyceride upon incubation with 1-palmitoyl-2-[1-(14)C]linoleoyl-PC-labeled HDL(3), indicating the ability of EL to supply cells with unsaturated FAs.

The mechanism responsible for the increase in concentration of free fatty acids in lipodystrophy was investigated in a 20-yr-old woman with a total absence of adipose tissues. The fasting concentration of plasma free fatty acid was not related to either the concentration of plasma glucose, immunoreactive insulin or growth hormone. The concentration of free fatty acid and glycerol did not increase significantly after the administration of norepinephrine. During a period on a high-fat diet the concentration of free fatty acids increased, and this was associated with an increase in the concentration of plasma triglycerides. The composition of free fatty acids in plasma closely resembled that of the plasma triglycerides. Post-heparin lipoprotein lipase activity was normal. It is suggested that circulating lipoprotein triglyceride was hydrolyzed by lipoprotein lipase on capillary surfaces at the peripheral sites and the resultant free fatty acids entered the circulation instead of being taken up by adipocytes, which were totally lacking in the patient. Insulinresistance decreased when the concentration of plasma free fatty acids decreased, suggesting that the elevation of free fatty acids was responsible for insulin-resistance in total lipodystrophy.

Influence of Mastitis on Properties of Milk. X. Fatty Acid Composition

Inflammation and oxidative stress play a pivotal role in COPD pathogenesis. Free fatty acids (FFA) as signaling molecules through a series of G-proteins coupled receptors, play an important role in regulation of the immune system and oxidative stress. For this reason, we decided to investigate the profile of FFA in the plasma in the COPD patients. This is a case-control study comparing 40 male patients with COPD and 40 healthy controls. Biochemical plasma parameters were measured by Autoanalyzer, Malondialdehyde by TBA, total antioxidant capacity via FRAP method and the concentration of free fatty acids were measured by gas chromatography. Then the relationship between the data and the spirometric findings of the patients was determined. In male COPD patients, fasting glucose, myristic acid, palmitic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, linolenic acid and total FFA showed a significant difference with the control group. Also, a positive correlation between the medium chain FFA and lung function was observed. The results of the present study showed that the concentration of different free fatty acids is different in healthy people and male COPD patients, and these differences, especially in the case of medium and long chain fatty acids, can be related to the lung function.

Changes in the concentration of long-chain free fatty acids were determined gas chromatographically from inside and outside muscle samples of brine- or plate-frozen Pacific halibut and chinook salmon stored for 9–81 weeks.With both species the concentration of individual free fatty acids was greater in outside muscle than in inside muscle. Few differences in concentration of free fatty acids were noted between plate- and brine-frozen samples. Numerous free fatty acids increased significantly in concentration during frozen storage. For both species the increase was most rapid during the first 26–45 weeks of storage. The detection of flavor differences was unrelated to the concentration of individual free fatty acids.

Fatty acid composition of the glycerine and free fatty acid fractions of the fat body, and hemolymph of the cockroach, Periplaneta americana (L.)

Plasma levels of free polyunsaturated fatty acids in patients with ischemic heart disease