Pitfalls in the use of 2-octynoic acid as an in vivo model of medium-chain acyl-coenzyme a dehydrogenase deficiency: Ketone turnover and metabolite studies in the rat

Fletcher, Janice M.; Pitt, James

doi:10.1016/s0026-0495(99)90165-8

Cited by 1 publication

(3 citation statements)

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“…Equations were adapted from Fletcher et al [ 26 ]. Briefly, when the two-pool model ( Figure 1 B) is at steady-state it can be represented by a system of 6 linear equations that describe all mass balances in the system.…”

Section: Methodsmentioning

confidence: 99%

“…The biochemical interconversion of these two ketones in peripheral tissue is too rapid to be considered independent, but too slow to be considered indistinguishable [ 21 ]. A dual-tracer technique that uses distinguishable AcAc and BHB tracers allowed both the dilution and the interconversion of each ketone to be determined [ 22 , 23 , 24 , 25 , 26 ] ( Figure 1 B). This approach substantially improved the accuracy of ketone turnover measurements compared to single-tracer approaches and closely matched net hepatic ketone production measured by an arterio-venous (A-V) balance technique [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

“…The standard two-pool model with two endogenous rates of appearance ( Ra ), two rates of disposal ( Rd ), and two rates of interconversion ( Ri ) requires solving six simultaneous equations [ 24 , 26 ]. Matrix approaches easily solve these equations from the two known rates of infusion ( Rinf ) and the measured dilution of the four tracer labeled species [ 26 ] ( Figure 1 B). However, the model assumes fidelity between tracer infusion rates and their dilution by endogenous ketone production and interconversion.…”

Section: Introductionmentioning

confidence: 99%

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In Vivo Estimation of Ketogenesis Using Metabolic Flux Analysis—Technical Aspects and Model Interpretation

Deja

Kucejová

et al. 2021

Metabolites

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Ketogenesis occurs in liver mitochondria where acetyl-CoA molecules, derived from lipid oxidation, are condensed into acetoacetate (AcAc) and reduced to β-hydroxybutyrate (BHB). During carbohydrate scarcity, these two ketones are released into circulation at high rates and used as oxidative fuels in peripheral tissues. Despite their physiological relevance and emerging roles in a variety of diseases, endogenous ketone production is rarely measured in vivo using tracer approaches. Accurate determination of this flux requires a two-pool model, simultaneous BHB and AcAc tracers, and special consideration for the stability of the AcAc tracer and analyte. We describe the implementation of a two-pool model using a metabolic flux analysis (MFA) approach that simultaneously regresses liquid chromatography-tandem mass spectrometry (LC-MS/MS) ketone isotopologues and tracer infusion rates. Additionally, 1H NMR real-time reaction monitoring was used to evaluate AcAc tracer and analyte stability during infusion and sample analysis, which were critical for accurate flux calculations. The approach quantifies AcAc and BHB pool sizes and their rates of appearance, disposal, and exchange. Regression analysis provides confidence intervals and detects potential errors in experimental data. Complications for the physiological interpretation of individual ketone fluxes are discussed.

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Section: Methodsmentioning

confidence: 99%