Free fatty acid determination by peroxidase catalysed luminol chemiluminescence

Näslund, Birgitta; Bernström, Kerstin; Lundin, Arne; Arner, Peter

doi:10.1002/bio.1170030305

Cited by 14 publications

(3 citation statements)

References 15 publications

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“…Protein content was assayed spectrophotometrically using the BCA Protein Assay Reagent Kit (Pierce, Rockford, IL) on 96-well microtiter plates with BSA as a standard. Glycerol was measured by bioluminescence (13) and fatty acid release by chemiluminescence (24).…”

Section: Methodsmentioning

confidence: 99%

Comparative studies of the role of hormone-sensitive lipase and adipose triglyceride lipase in human fat cell lipolysis

Rydén¹,

Jocken²,

Harmelen³

et al. 2007

American Journal of Physiology-Endocrinology and Metabolism

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115

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Hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) regulate adipocyte lipolysis in rodents. The purpose of this study was to compare the roles of these lipases for lipolysis in human adipocytes. Subcutaneous adipose tissue was investigated. HSL and ATGL protein expression were related to lipolysis in isolated mature fat cells. ATGL or HSL were knocked down by RNA interference (RNAi) or selectively inhibited, and effects on lipolysis were studied in differentiated preadipocytes or adipocytes derived from human mesenchymal stem cells (hMSC). Subjects were all women. There were 12 lean controls, 8 lean with polycystic ovary syndrome (PCOS), and 27 otherwise healthy obese subjects. We found that norepinephrine-induced lipolysis was positively correlated with HSL protein levels (P < 0.0001) but not with ATGL protein. Women with PCOS or obesity had significantly decreased norepinephrine-induced lipolysis and HSL protein expression but no change in ATGL protein expression. HSL knock down by RNAi reduced basal and catecholamine-induced lipolysis. Knock down of ATGL decreased basal lipolysis but did not change catecholamine-stimulated lipolysis. Treatment of hMSC with a selective HSL inhibitor during and/or after differentiation in adipocytes reduced basal lipolysis by 50%, but stimulated lipolysis was inhibited completely. In contrast to findings in rodents, ATGL is of less importance than HSL in regulating catecholamine-induced lipolysis and cannot replace HSL when this enzyme is continuously inhibited. However, both lipases regulate basal lipolysis in human adipocytes. ATGL expression, unlike HSL, is not influenced by obesity or PCOS.

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Section: Methodsmentioning

confidence: 99%

Comparative studies of the role of hormone-sensitive lipase and adipose triglyceride lipase in human fat cell lipolysis

Rydén¹,

Jocken²,

Harmelen³

et al. 2007

American Journal of Physiology-Endocrinology and Metabolism

Self Cite

115

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show abstract

“…Another aliquot was used for the measurement of FFA release from fat cells, using a chemiluminescence method (35). FFA oxidation in this in vitro system is negligible (36), so the only expected outcomes for the FFA are either release from the fat cells during lipolysis or re-esterification.…”

Section: Subjects-mentioning

confidence: 99%

Mechanisms Involved in the Regulation of Free Fatty Acid Release from Isolated Human Fat Cells by Acylation-stimulating Protein and Insulin

Harmelen

Reynisdottir

Cianflone

et al. 1999

Journal of Biological Chemistry

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149

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The effects of acylation-stimulating protein (ASP) and insulin on free fatty acid (FFA) release from isolated human fat cells and the signal transduction pathways to induce these effects were studied. ASP and insulin inhibited basal and norepinephrine-induced FFA release by stimulating fractional FFA re-esterification (both to the same extent) and by inhibiting FFA produced during lipolysis (ASP to a lesser extent than insulin). Protein kinase C inhibition influenced none of the effects of ASP or insulin. Phosphatidylinositol 3-kinase inhibition counteracted the effects of insulin but not of ASP. Phosphodiesterase 3 (PDE3) activity was stimulated by ASP and insulin, whereas PDE4 activity was slightly increased by ASP only. Selective PDE3 inhibition reversed the effects of both ASP and insulin on fractional FFA re-esterification and lipolysis. Selective PDE4 inhibition slightly counteracted the ASP but not the effect of insulin on fractional FFA re-esterification and did not prevent the action of ASP or insulin on lipolysis. Thus, ASP and insulin play a major role in regulating FFA release from fat cells as follows: insulin by stimulating fractional FFA re-esterification and inhibiting lipolysis and ASP mainly by stimulating fractional FFA re-esterification. For both ASP and insulin these effects on FFA release are mediated by PDE3, and for ASP PDE4 might also be involved. The signaling pathway preceding PDE is not known for ASP but involves phosphatidylinositol 3-kinase for insulin.

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“…For studies of the enzyme kinetics of urease, this twostep procedure is not suitable and therefore alternative methods, using for example chemiluminescence [26], or ammonium-selective electrodes [27] have been developed for this purpose. Duffy et al [28] described the batch wise use of a specially designed cell for measurement of the increase in bulk conductance due to the charged products obtained in the enzymatic conversion of urea.…”

Section: Introductionmentioning

confidence: 99%

Development and Validation of a Chromatographic and Electrophoretic Method for the Determination of Amikacin and Urea in Bronchial Epithelial Lining Fluid

et al. 2012

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Methods were developed to determine amikacin and urea in bronchial epithelial lining fluid of neonates. Urea was determined as ammonium by capillary electrophoresis in combination with capacitively coupled contactless conductivity detection (CE-C 4 D). The ammonium was produced by enzymatic conversion of urea with urease enzyme. The background electrolyte (BGE) contained 30 mM malic acid, adjusted to pH 4.1 by L-arginine, and 10 mM 18-Crown-6. Lithium was used as internal standard. A ?30 kV was applied on a fused silica capillary with 75 lm internal diameter (ID) and total length of 65 cm (41 cm to C 4 D detector). The optimized separation was obtained in \3 min with good linearity (R 2 = 0.9998) for urea concentrations ranging from 0.6 to 24 mg L -1 . It also shows a good repeatability expressed by the RSD which is 0.7 and 1.3 % for intraday and interday precision, respectively. The LOD and LOQ are 0.14 and 0.5 mg L -1 respectively. As the CE-C 4 D method was not sensitive enough for amikacin, the latter was determined using liquid chromatography combined with pulsed electrochemical detection (LC-PED). The LOQ for amikacin base was found to be 0.06 mg L -1 . In addition, the linearity was good (R 2 [ 0.995) as well as the repeatability (RSD = 0.1 %, n = 3). For both the CE and LC method, no interference of matrix components was observed and the recoveries were found to be close to 100 %.

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Free fatty acid determination by peroxidase catalysed luminol chemiluminescence

Cited by 14 publications

References 15 publications

Comparative studies of the role of hormone-sensitive lipase and adipose triglyceride lipase in human fat cell lipolysis

Comparative studies of the role of hormone-sensitive lipase and adipose triglyceride lipase in human fat cell lipolysis

Mechanisms Involved in the Regulation of Free Fatty Acid Release from Isolated Human Fat Cells by Acylation-stimulating Protein and Insulin

Development and Validation of a Chromatographic and Electrophoretic Method for the Determination of Amikacin and Urea in Bronchial Epithelial Lining Fluid

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