- XF Applications
- Substrate Utilization
- Mitochondrial Function
- Energy Expenditure
- Cell Quality Assessment
- Cell Line Reference
Substrate Utilization
Traditionally, metabolic fluxes associated with energy metabolism are determined from accumulation of radionucleotide in a metabolite derived from a labeled substrate. For example, accumulation of 3HOH water from 3-3H-D-glucose is a measure of glycolytic flux through GAPDH. These types of radiometric assays can be highly specific, but they are also very labor intensive, can lack precision and often require substantial quantities of tissue or cells.
Recent work has shown that XF assays can provide estimates of metabolic fluxes with more information than those obtained with the radiometric assays for several different substrates including glucose, galactose, glutamine, pyruvate, palmitate and oleate. The advantages to the XF assays are higher throughput, reduced sample sizes and substantially-improved kinetic resolution with rates that are typically obtained within several minutes. In many ways these extracellular flux assays recapitulate the classical methods used to study isolated mitochondria with the added advantage of using whole cells or tissue to retain intact cytoplasmic processes and signaling.
The high content of XF assay data over radiometric data has influenced critical lead compound decisions in large pharmaceutical companies.
Direct Comparison of Radiometric versus XF24 Flux Assays to Measure Substrate Utilization
Traditionally, metabolic fluxes associated with energy metabolism are measured as the time-dependent accumulation of radionucleotide in a metabolite that is derived from a labeled substrate. This application note describes the advantages of the XF assay which includes non-radiometric, label-free, reduced samples sizes and significantly improved kinetic resolution with rates that are typically obtained in minutes.
Fatty Acid Oxidation in C2C12 Myocytes and Agonist Response to an ACC Inhibitor and Metformin
Measuring the effects of compounds on Fatty Acid Oxidation (FAO) in mammalian cells typically involves using radioactive materials and is time consuming. This application demonstrates how XF assays provide comparable performance to radiometric methods, with better throughput and without the use of radioactive materials.