Variations In Free Fatty Acids Research Articles

Differential effects of bariatric surgery on plasma levels of ANGPTL3 and ANGPTL4

Background and aimAngiopoietin-like 3 (ANGPTL3) and 4 (ANGPTL4) are regulators of triglyceride storage and utilization. Bariatric surgery (BS) leads to profound changes in adipose tissue composition and energy metabolism. We evaluated the impact of BS on plasma levels of ANGPTL3 and ANGPTL4. Methods and resultsTwenty-seven subjects affected by morbid obesity with or without type 2 diabetes (T2D) underwent Roux-en-Y gastric bypass (RYGB) and 18 patients with advanced T2D received Biliopancreatic Diversion (BPD). Fasting ANGPTL proteins levels, insulin sensitivity (evaluated by euglycemic hyperinsulinemic clamp), total bile acids (TBA) and free fatty acids (FFA) were measured at baseline and 1 year after surgery.Both surgical procedures resulted in the loss of fat mass, improved glucose control, and a ∼2-fold increase of insulin sensitivity. ANGPTL4 levels decreased significantly with both RYGB (26.6 ± 0.6 to 24.4 ± 0.3 ng/mL, p = 0.001) and BPD (27.9 ± 1.5 to 24.0 ± 0.5 ng/mL, p = 0.003). In contrast, ANGPTL3 concentrations did not change after RYGB but rose following BPD (225 ± 20 to 300 ± 15 ng/mL, p = 0.003). By multiple regression analysis, changes after BS in ANGPTL4 were independently associated with changes in blood glucose, (p = 0.0169) whereas changes in ANGPTL3 were associated with variations in FFA (p = 0.008) and insulin sensitivity (p = 0.043). ConclusionCirculating ANGPTL4 is reduced by BS, probably due to the loss of fat mass and improved insulin sensitivity. Conversely, ANGPTL3 levels increased after BPD, but not after RYGB, presumably because of the metabolic changes induced by the malabsorptive effect of BPD.

Investigation of biodiesel production methods by altering free fatty acid content in vegetable oils

ABSTRACTBiodiesel is derived from vegetable oils and animal fats by various methods among which transesterification is the most widely used. The present work explores the effects of variations in free fatty acids (FFA) of vegetable oils on the biodiesel production methodology as well as on the yield. Three vegetable oils, viz. corn, neem and rubber seed, having FFAs of 0.28, 12.1 and 47.1%, respectively, are mixed in various proportions to get 19 oil samples with FFAs varying from 0.28 to 47.1%. An alkali transesterification method is used for oil samples having FFAs ranging from 0.28 to 5%. The biodiesel yield is around 95% for oils having FFA below 2%; however, it drops below 80% for oils with FFA above 3.6%, while the process fails for oils with FFA above 4.2%. A multi-stage acid–base transesterification process is employed for oils having high FFA, above 6%. A single-stage acid pretreatment process is found to be enough for oils with FFA up to 24%, and a multi-step pretreatment is required thereafter. The measured viscosity, density and calorific value of all the biodiesels are found to be well within the international standard specifications.

Lipolysis and Lipid Oxidation during Processing of Chinese Traditional Dry-Cured White Amur Bream (Parabramis pekinensis)

ABSTRACTLipolysis and lipid oxidation of intramuscular lipids during the dry-curing process of white amur bream (Parabramis pekinensis) were studied. All lipolytic enzyme activities decreased (p < 0.05) at the end of the process. The lipoxygenase activity increased during wet-salting (p < 0.05) and then decreased until the end of the process (p < 0.05). The daily variation of free fatty acids was correlated with those of the peroxide value (r = 0.976, p < 0.01) and thiobarbituric acid-reactive substances (r = 0.922, p < 0.01), respectively. These results suggest that lipolysis promotes lipid oxidation during the processing of dry-cured fish.

Metabolic Regulation in Danish Bull Calves and the Relationship to the Fertility of Their Female Offspring

The objective of this work was to estimate the genetic variation of free fatty acids (FFA), glucose, growth hormone (GH), and insulin in juvenile male dairy calves and to assess the relationships, if present, with the fertility of their female offspring. This study used data from 1,498 (269.5 d of age±11.1) male calves from a multiple ovulation and embryo transfer breeding scheme (data collected from 1997 to 2002). Calves were Danish Holstein (n=1,047), Danish Jersey (n=200), and Red Dane (n=251), and were sampled following an overnight fast at approximately 9 mo of age. Plasma samples were assayed for basal FFA, glucose, GH, and insulin. Estimated breeding values of female fertility (high values indicating better fertility), based on progeny-test results for approximately 100 daughters per sire, were available for a subset (n=810) of the male calves as adult sires. Data from Danish Holstein alone or Danish Holstein, Red Dane, and Danish Jersey combined (all breeds) were analyzed for each trait. In both data sets, the estimates of heritabilities of glucose (0.27±0.06), FFA (0.11±0.05), and insulin (0.21±0.06) were moderate, and that of GH (0.09±0.05) was low. Correlations of estimated breeding values for fertility traits with glucose and FFA breeding values were negative, indicating that male calves with high glucose or FFA had female offspring with reduced fertility. Selection for bull calves with lower concentrations of glucose and FFA following an overnight fast could result in female offspring with genetically better fertility. Glucose and FFA may therefore be of interest to enhance selection for improved female fertility, as a measurement in young bulls.

Effect of recombinant human GH and GHRH on plasma metabolite levels in rainbow trout (Oncorhynchus mykiss)

The aim of the present work was to study metabolic changes in rainbow trout treated with preparations of human recombinants of growth hormone (rhGH) and GH-releasing hormone (rhGHRH), by analysing time course variations in plasma metabolite levels. Trouts were given the hormones by intraperitoneal injection in a single dose (rhGH: 0.5microg/g b.w.; rhGHRH: 0.06microg/g b.w.) or as a weekly injection over a period of 4 weeks. The concentrations of glucose, lactate, free fatty acids and glycerol were determined in plasma immediately before injection and 1, 3, 6, 12, 24, 48 and 168 hours post-injection. Results indicate that glucose and lactate levels increase, while slight variations in free fatty acids was observed after the injection of rhGH and rhGHRH.

Postprandial free fatty acids stimulate activity of human corticosteroid binding globulin.

The effect of postprandial variation of free fatty acids (FFA) on serum corticosteroid binding globulin (CBG) properties and cortisol (hydrocortisone) concentrations were explored in 11 women (20-30 yr) during 8 h after an oral load of tallow (26% C16:0, 18% C18:0, and 43% C18:1), oleic-sunflower (oleic-SF; 73% C18:1), sunflower (SF; 67% C18:2), and mixed oil (MO; 39% C18:1 and 48% C18:2). Serum FFA increased little after SF and MO but more than doubled in the late postprandial period (6 and 8 h) after oleic-SF (due to monounsaturated FFA) or tallow (due to saturated and monounsaturated FFA). CBG concentrations remained unchanged, but in relation with the postprandial elevation of serum FFA, CBG binding activity was increased after tallow or oleic-SF as a result of a combined two- to threefold increase in affinity constant and a 50% reduction in binding sites. Immunological and in vitro binding studies showed the changes in CBG behavior to be conformational and to be mediated mainly by monounsaturated FFA, especially C18:1. The modifications of CBG properties were associated with sustained high concentrations of cortisol (suppression of midday decrease) 6 and 8 h after tallow or oleic-SF. Thus dietary FFA may have an impact on bioavailability of glucocorticoids.

Nonfatty acid-modulated variations in drug binding due to heparin.

Changes in free fatty acids (FFAs) do not always correlate with variations in drug binding. To dissociate heparin effects on FFAs and drug binding, six healthy fasting subjects received 50 units (USP) IV heparin (Harris L932) with and without protamine (3.2 mg IV). Protamine completely suppressed heparin-induced rises in FFAs and warfarin free fraction (W alpha), but diazepam free fraction (D alpha) increased (P less than 0.005). In vitro, increasing concentrations of heparin added to serum increased D alpha (P less than 0.0005) and W alpha (P less than 0.005) without changing FFAs. In eight subjects given 50 units IV heparin (Harris L014), FFAs (P less than 0.001) and propranolol free fraction (P alpha) rose (P less than 0.01), but variations in FFAs and P alpha did not correlate (r = 0.18). When two different heparin lots (Harris L014 and Organon LA39) were tested in vivo. Harris L014 heparin increased FFAs (P less than 0.005) and P alpha (P less than 0.0005), but variations in FFAs and P alpha correlated poorly (r = 0.43, P less than 0.05). In contrast, the Organon LA39 heparin did not change FFAs, but did increase P alpha (P less than 0.0005); variations in FFAs and P alpha did not correlate (r = 0.22). These results indicate that heparin-induced variations in drug binding are not exclusively related to changes in FFAs.

Sex variations in free fatty acids and ketones during fasting: evidence for a role of glucagon.

Women differ markedly from men in their metabolic response to caloric deprivation. To determine if these differences could be attributed solely to changes in insulin concentration, a group of 8 women was matched with a group of 7 men so that the mean fall in serum insulin during a 72-h fast did not differ between the groups. Glucose levels fell to a greater degree in the women than in the men. The serum concentrations of free fatty acids and ketone bodies rose more rapidly in the women and closely paralleled the earlier rise in glucagon concentrations. Over the first 36 h of fasting the change in free fatty acids was positively correlated to the change in glucagon and negatively correlated to the change in insulin. For the second 36 h of fasting, only changes in glucagon correlated with changes in free fatty acids. These correlations were true for both sexes and support the hypothesis that glucagon plays a physiologically significant role the regulation of lipolysis during starvation.