Colorimetric micro-determination of free fatty acids in plasma

Laurell, S.; Tibbling, G

doi:10.1016/0009-8981(67)90269-0

Cited by 465 publications

(115 citation statements)

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“…Total serum proteins were assayed using the Biuret method (Gomall et al, 1949), albumin concentrations were quantitated by gel electrophoresis (Sepratek, Gelman Sciences, Ann Arbor, MI), free fatty acids (FFA) were measured colorimetrically (Laurell & Tibbling, 1967) and AAG levels were quantitated by radial immunodiffusion (Mancini et al, 1965) (Figure 1), revealed that -78% of the variability of PP binding could be accounted for by considering AAG concentrations.…”

Section: Introduction Methodsmentioning

confidence: 99%

Serum alpha 1‐acid glycoprotein and the binding of drugs in obesity.

Benedek¹,

d²,

Wo³

et al. 1983

Brit J Clinical Pharma

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Although clinically relevant, drug-protein interactions in the morbidly obese population have not been studied thoroughly. The objective of this study was to evaluate serum chemistry profiles and the degree of serum protein binding of propranolol, diazepam and phenytoin in the serum of four female, morbidly obese (> 190% of ideal body weight) and eight control female subjects. Serum triglyceride concentrations were higher and high-density lipoproteins were lower in the obese subjects than in the control group. Serum albumin and total protein concentrations in the obese were not different from controls. Unexpectedly, a,-acid glycoprotein concentrations were doubled in the obese subjects (mean obese value 121 mg 100 ml vs 62.9 mg, 100 ml for the control subjects). Obese subjects had a mean fraction unbound (fu) for propranolol of 0.086, which was significantly different from the controls (f, = 0.123). The binding of diazepam was decreased slightly in the obese subjects. The binding of phenytoin was similar in both groups.The altered serum chemistry of obesity may play a significant role in the drug management of the obese patient by altering drug-protein interactions.

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Section: Introduction Methodsmentioning

confidence: 99%

Serum alpha 1‐acid glycoprotein and the binding of drugs in obesity.

Benedek¹,

d²,

Wo³

et al. 1983

Brit J Clinical Pharma

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“…They are generally based on the partially specific extraction of lipids by organic solvents associated with the elimination of interfering compounds such as phospholipids or volatile fatty acids (Dole and Meinertz, 1960 ;Trout, Estes and Friedberg, 1960 ;Duncombe, 1964 ;Antonis, 1965 ;Itaya and Ui, 1965 ;Laurell and Tibbling, 1967 ;Falholt, Lund and Falholt, 1973). After extraction, the carboxylic groups can be determined by titrimetry (Dole, 1956) or by manual (Laurell and Tibbling, 1967 ;Duncombe, 1963 ;Mosinger, 1965 ;Novak, 1965) or automatic (Antonis, 1965 ;Baird, Black and Faulkner, 1967) colorimetry.…”

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confidence: 99%

“…After extraction, the carboxylic groups can be determined by titrimetry (Dole, 1956) or by manual (Laurell and Tibbling, 1967 ;Duncombe, 1963 ;Mosinger, 1965 ;Novak, 1965) or automatic (Antonis, 1965 ;Baird, Black and Faulkner, 1967) colorimetry. Recently, several enzymatic techniques have been developed that use acyl-Co-A synthetase for plasma NEFA specific assay without previous extraction (Mizuno et a/., 1980 ;Okabe et al, 1980 ;Shimizu et al, 1980 ;Hosaka et al, 19811. The reason why there are so many methods for determining NEFA is that there are a number of still unresolved difficulties in obtaining both a quantitative and a specific assay (without interfering substances).…”

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confidence: 99%

“…Methodological studies on herbivore plasma are scarce (Crane and Lane, 1977 ;De Villiers, Van Der Walt and Procos, 1977 ;Bas, 1984) ; most have been carried out on human or rat plasma. Very few methods have been compared to a specific and quantitative reference method (Duncombe and Rising, 1973 ; Donald-Gibson and Young, 1974 ;Brunck and Swanson, 19811, the majority (ltaya and Ui, 1965 ;Laurell and Tibbling, 1967 ;Mosinger, 1965 ;Howorth, Gibbard and Mark, 1966 ;Lorch and Gey, 1966 ;Baird, Black and Faulkner, 1967 ;Dalton and Kowalski, 1967 ;Kashket, 1971 ;Soloni and Sardina, 1973 ;Elphick, 1975 ;Bowyer, Cridland and King, 1978 ;Shimizu et al, 1980) being contrasted with the titrimetric determination of Dole and Meinertz (1960) or Trout, Estes and Friedberg (1960). Enzymatic techniques were mainly compared with the colorimetric determination of copper soaps (Mizuno et al, 1980 ;Shimizu et al, 1980 ;Hosaka et al, 1981 ;Bas, 1984) HIA method (heptane-isopropanol-sulfuric acid).…”

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confidence: 99%

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Determination of plasma non-esterified fatty acids in herbivores and man : a comparison of values obtained by manual or automatic chromatographic, titrimetric, colorimetric and enzymatic methods

Chilliard¹,

Bauchart²,

Barnouin³

et al. 1984

Reprod. Nutr. Dévelop.

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Summary. Non-esterified fatty acid (NEFA) contents were determined (1) in cow, goat, mare and human plasmas or sera and (2) in bovine serum albumin solutions by thin-layer and gas-liquid chromatographic methods which were compared with 6 chemical methods of determination and 2 enzymatic methods (manual and automatic). The chemical methods combined two extraction techniques (isopropanol-heptane and silicic acid-diisopropyl ether) and three determination methods (titrimetry and colorimetry using either phenol red or copper soaps). Correlations between the nine various methods were high, but in some cases regression lines were different from the bissector and species-dependent. The putative occurrence of interfering compounds or the possible effect of between-species differences in NEFA composition have been discussed. The choice of a fast method depends primarily on practical considerations, but the need to standardize each method for a given species has been stressed. Automatic enzymatic assay seemed to be suitable for routine analyses.Introduction.

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“…Plasma UFA was determined by the method of Laurell & Tibbling (1967). Brain tryptophan and tyrosine and plasma tyrosine, were measured as previously described .…”

Section: Methodsmentioning

confidence: 99%

Rapid Effects of Environmental Disturbance on Rat Plasma Unesterified Fatty Acid and Tryptophan Concentrations and Their Prevention by Antilipolytic Drugs

Curzon¹,

Knott²

1975

British J Pharmacology

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1Changes of plasma unesterified fatty acid (UFA) and tryptophan concentration in group-housed rats following removal of their cage-mates and the effects of antilipolytic drugs on these changes were investigated. 2 Removal of group-housed 24 h fasted rats but not fed rats from cages resulted in increased plasma UFA concentration in the remaining rats which was associated with significant increases of the proportion of free tryptophan but significant falls of total tryptophan concentration. These rapid changes were not associated with brain tryptophan changes. Plasma tyrosine concentration was unaffected. 3 The fall of plasma tryptophan did not appear to be due to passage into red cells as erythrocyte tryptophan concentration remained unchanged. 4 Plasma UFA concentrations correlated positively and significantly with corticosterone concentrations which were also increased following removal of cage-mates. 5 Plasma UFA increases and tryptophan changes in the fasting rats were both prevented by nicotinic acid or propranolol. Corticosterone concentration was increased by nicotinic acid but unaffected by propranolol. 6 The possible importance of these rapid changes of plasma tryptophan and of their prevention by antilipolytic drugs is discussed.

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Colorimetric micro-determination of free fatty acids in plasma

Cited by 465 publications

References 8 publications

Serum alpha 1‐acid glycoprotein and the binding of drugs in obesity.

Serum alpha 1‐acid glycoprotein and the binding of drugs in obesity.

Determination of plasma non-esterified fatty acids in herbivores and man : a comparison of values obtained by manual or automatic chromatographic, titrimetric, colorimetric and enzymatic methods

Rapid Effects of Environmental Disturbance on Rat Plasma Unesterified Fatty Acid and Tryptophan Concentrations and Their Prevention by Antilipolytic Drugs

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