Extracellular Acidification Rate
Extracellular Acidification Rate - Related Videos
06:47
Measurement and Analysis of Extracellular Acid Production to Determine Glycolytic Rate
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Cited by 103 •
2015
Glycolysis is a defining metabolic marker in multiple biological systems. Monitoring glycolysis by measuring the extracellular flux of H+ is common, but requires correction to be quantitative and unambiguous. Here, we demonstrate how to gather and correct extracellular flux data to distinguish between respiratory and glycolytic sources of extracellular acidification.
03:21
Gut Acidification Monitoring Assay: A Technique to Study the Acidification of the Intestinal Lumen in Drosophila using Bromophenol Blue Dye
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2025
This video demonstrates an assay to monitor gut acidification in Drosophila flies. After the ingestion of food supplemented with a pH indicator dye, the acidification of the intestinal lumen results in a change in the color of the dye. Visual inspection of the digestive tract of the flies to examine the color change provides evidence of acidification.
06:15
Assessing the Metabolic Activity of Whole Regenerating Zebrafish Ventricles Ex Vivo Using an Extracellular Flux Assay
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2026
In this article, we describe a detailed protocol for quantifying the oxygen consumption rate and extracellular acidification rate of ex vivo adult zebrafish ventricles to characterize their oxidative and glycolytic metabolic capacity.
04:39
Extracellular Flux Assay: A Method for Measuring Metabolic Profile of Cells
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2023
This protocol provides a biochemical approach for measuring extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) of primary leukemic cells with extracellular flux assay. The assessment of the metabolic profile of these cells helps to characterize their demands, leading to personalized therapy.
04:39
Monitoring Gut Acidification in the Adult Drosophila Intestine
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Cited by 10 •
2021
Here, we present a standardized protocol for monitoring gut acidification in Drosophila melanogaster with optimal output. We first use this protocol for gut acidification monitoring in Drosophila melanogaster and then demonstrate its use in non-model Drosophila species.
FAQs
ECAR can increase when cells convert glucose to lactate and export lactate together with protons into the surrounding medium. This links the signal to glycolytic flux, but the relationship is not exclusive because respiration and other transport processes can also alter extracellular pH. Consequently, ECAR is best interpreted as an indicator of acidifying metabolic activity rather than a direct, standalone measurement of glycolysis.
Proton and lactate export provides an important route by which glycolytic metabolism changes the extracellular environment. Greater export can produce a stronger acidification signal, whereas altered transport may change ECAR without an equivalent change in glucose conversion. Considering both metabolism and transport helps distinguish changes in glycolytic activity from changes in how cells release acidifying products.
ECAR does not originate from glycolysis alone. Respiratory activity and additional transport processes may contribute to proton accumulation or removal around living cells, changing the measured rate. This matters when comparing conditions, because an ECAR difference may reflect a broader shift in cellular physiology rather than an isolated alteration in glycolytic flux. Interpretation therefore requires attention to the experimental context.
A change in ECAR can indicate that cells have altered their metabolic activity, glycolytic flux, or ability to adjust metabolism under different conditions. Examining the response over time can help characterize metabolic flexibility, meaning how cells adapt their energy-related activity to compounds or nutrient changes. The result is especially useful for comparing cellular responses rather than assigning a single cause automatically.
In a live-cell assay, cells are maintained in their surrounding medium while a pH-sensitive sensor detects changes caused by proton accumulation outside the cells. The measurement is recorded in real time as a rate, allowing investigators to follow dynamic responses rather than relying only on an endpoint. Researchers can then compare acidification before and after compounds or nutrient conditions change.
ECAR measurements support studies of bioenergetics, cancer metabolism, immune-cell function, and general cellular physiology. Investigators may use the assay to examine how cells respond to compounds or altered nutrient conditions and to assess metabolic flexibility. Because the readout captures extracellular acidification from living cells over time, it can reveal functional metabolic responses that static measurements may not show.