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Bicarbonate alters cellular responses in respiration assays

Author:
Krycer, James R., Fisher-Wellman, Kelsey H., Fazakerley, Daniel J., Muoio, Deborah M., James, David E.
Source:
Biochemical and biophysical research communications 2017 v.489 pp. 399-403
ISSN:
0006-291X
Subject:
adipocytes, alkalinization, bicarbonates, bioassays, buffers, enzymes, hepatocytes, insulin resistance, mitochondria, myotubes, pH
Abstract:
Metabolic assay buffers often omit bicarbonate, which is susceptible to alkalinisation in an open environment. Here, we assessed the effect of including bicarbonate in respirometry experiments. By supplementing HEPES-buffered media with low concentrations of bicarbonate, we found increased respiration in adipocytes and hepatocytes, but not myotubes. This was observed across multiple respirometry platforms and was independent of effects on enhanced insulin sensitivity, pH drift, or mitochondrial function. Permeabilised cell experiments suggest that bicarbonate increases substrate availability, likely by acting as a cofactor for carboxylase enzymes. This emphasises the importance of buffer choice in experimental biology.
Agid:
5729266