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Extracellular acidification parallels insulin secretion in INS-1 and HIT-T15 beta-cell lines
Douglas B Luckie1, John H Wilterding, Joseph J Maleszewski
1Department of Physiology, 2100 Biomedical and Physical Sciences Bldg., Michigan State University, East Lansing, MI 48824-1101, USA. luckie@msu.edu
Abstract:
As an alternative to manual assays that track insulin secretion, we tested a silicon-based biosensor that allows automated monitoring of extracellular acidification. Glucose stimulation of INS-1 and HIT-T15 cells resulted in a rapid increase in extracellular acidification in a biphasic and concentration-dependent fashion much like insulin secretion (EC(50) INS-1=5 mM and HIT-T15=1 mM). This response was attenuated by verapamil (10 microM) and stimulated by administration of glybenclamide (100 nM) or KCl-induced (40 mM) depolarization. These experiments suggest that automated monitoring of extracellular pH may be a useful assay and support the relevance of linking metabolic activity to insulin secretion.