Blood Plasma Free Fatty Acids Research Articles

Chromatographic–mass spectrometric determination of free fatty acids in blood plasma and urine using extractive alkylation

A method is proposed for the extractive alkylation of free fatty acids (FFA) in blood plasma and urine for their subsequent chromatographic–mass spectrometric determination as methyl esters. The list of target compounds includes 19 saturated acids (C6–C24) and 20 unsaturated acids (C16–C24), including ω-3, ω-6, ω-9, and polyunsaturated fatty acids. For the simultaneous extraction of FFA from a matrix and derivatization, extractive alkylation with iodomethane was used. The peculiarity and advantage of the method is integration of the stages of extraction and preparation of volatile derivatives under mild conditions. The recovery and conversion are from 60 to 90%. The analytical range was from 0.02 to 20 µg/mL of a sample. The effect of samples storage conditions on the results of measurements is evaluated. The method was tested in the determination of FFA in blood plasma and urine of volunteers and laboratory animals.

Utilisation of energy substrates in treadmill-exercised domestic fowl (Gallus gallus domesticus): blood plasma free fatty acids.

1. Plasma free fatty acid (FFA) concentration, FFA turnover and gas exchange were measured in adult male domestic fowl at rest and during 90 min continuous treadmill exercise at a work load of approximately three times the resting metabolic rate. 2. Plasma FFA concentration and turnover increased 7-fold and 4-fold respectively during exercise. Of the FFA turnover 0.54 was oxidised at rest and this increased to 0.70 during exercise. The fraction of the total carbon dioxide production derived from plasma FFA oxidation rose from 0.33 at rest to 0.55 during exercise. 3. It is concluded that plasma FFA are the most important source of energy for the working muscles of domestic fowl during treadmill exercise of this intensity and duration.

Inhibition of sperm motility and agglutination of sperm cells by free fatty acids in whole semen

The effects of a serial dilution of linoleic acid on human spermatozoa in whole semen was tested on 21 semen samples obtained from 11 normal volunteers. The minimal concentration of linoleic acid required to stop the movement of at least 75% of the moving sperm ranged from 1 to greater than 100 mg/dl. Fifteen of 21 (71%) of the semen samples were inhibited by added free fatty acids (FFA) concentrations that were less than or close to the physiologic concentration ranges of FFA in blood plasma (1 to 30 mg/dl). The immobilized sperm often formed aggregates similar to those formed by the action of autoantibodies against sperm cells. Preliminary studies conducted on a variety of other FFA have indicated that oleic acid (18/1) was less toxic than linoleic acid (18/2) and that linolenic acid (18/3) was more toxic than linoleic acid. The saturated FFA palmitic acid (16/0) and stearic acid (18/0) at concentrations up to 100 mg/dl showed little or no toxicity to sperm cells. It is suggested that FFA toxicity be included among physiologic factors that affect the motility and spontaneous aggregation of sperm cells.

Effects of cloprostenol administration on neutral lipid and prostaglandin F metabolism by porcine luteal tissue

The effects of Cloprostenol administration on porcine luteal lipid metabolism, progesterone production, and prostaglandin F production were examined in 32 pigs at day 12 of the estrous cycle. Pigs were killed between 0 and 18 hours after treatment. Recovered luteal tissue was incubated at 0 C and at 37 C in the absence and presence of dibutyryl cyclic AMP and indomethacin. Net in vitro release of progesterone from luteal tissue was depressed within 1 hour after Cloprostenol treatment whereas net in vitro release of prostaglandin F was accelerated 4 hours after Cloprostenol treatment. Inclusion of dibutyryl cyclic AMP in the incubation media did not alter progesterone production by did enhance prostaglandin F production at 0 and 1 hour after Cloprostenol treatment. Inclusion of indomethacin in the incubation media completely inhibited the Cloprostenol-induced acceleration of in vitro luteal PGF production. Cloprostenol treatment increased luteal triglycerides and decreased luteal free cholesterol and cholesterol esters within 1 hr after treatment. Arachidonic acid percentages in free fatty acids and triglycerides were also increased within 1 hr after treatment. When 37 C and 0 C incubations were compared, in vitro luteal accumulation of free fatty acids was maximum at 1 hr after Cloprostenol treatment. In vitro accumulation of triglycerides in luteal tissie was comparatively uniform at all times examined during the first 18 hr after Cloprostenol treatment. Comparison of 37 C and 0 C incubations further revealed that luteal triglycerides were active in accumulation of arachidonic acid. Inclusion of dibutyryl cyclic AMP and/or indomethacin in the incubation media did not alter luteal lipid contents or fatty acid compositions. Blood plasma progesterone was depressed at 4 hours after Cloprostenol whereas 13,14-dihydro-15-keto-prostaglandin F2a was elevated at 18 hours after treatment. Blood plasma free fatty acids increased 330 percetn at 4 hours and free fatty acid compositions also changed at this time. In both luteal tissue and blood plasma, changes in steroid and fatty acid metabolism occurred prior to changes in prostaglandin metabolism, suggesting that Cloprostenol induced functional luteal regression prior to altering prostaglandin metabolism.

Influence of a Fat Mobilizing Substance from Chicken Urine on Geese

A fat mobilizing substance, obtained from chicken urine, was injected intravenously in geese. The effect of this substance on geese was similar to that obtained on chickens, i.e. an increase in blood plasma free fatty acids; a decrease in plasma lipids and feed intake.

Metabolism of free fatty acids during perinatal life of lambs

1.1. Studies of the mechanisms responsible for the rapid rise in the concentration of free fatty acids (FFA) in blood plasma after birth were done in newborn lambs.2.2. From changes in the specific radioactivity of free fatty acids of plasma during constant intravenous infusion of palmitate 1-C14 it was shown that the increase in plasma concentration of FFA after birth is the result of augmented mobilization of free fatty acids into the blood. This mobilization was reversed by blocking transmission at autonomic ganglia with hexamethonium.3.3. Intravenous injection of approximately 50 μg norepinephrine per kilogram body weight was required to increase FFA in blood plasma of newborn lambs; 2 μg per kilogram body weight was effective in ewes.4.4. Sensitivity to the effect of norepinephrine was not increased by fasting newborn lambs up to 40 hours, and increased sensitivity could not be demonstrated until the lambs were 8 weeks old.5.5. The results are compatible with the concept that increased activity of sympathetic nerves innervating adipose tissue is an important factor in the rapid mobilization of FFA into the blood after birth, and suggest that secretion of norepinephrine from the adrenal medulla is not involved.