Na +/H + exchange is responsible for intracellular pH regulation in insulin-secreting HIT-T15 cells

• Published in: Molecular and cellular endocrinology Vol. 71; no. 1; pp. 21 - 25
• Main Authors: Trebilcock, Richard, Lynch, Angela, Tomlinson, Stephen, Best, Leonard
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 28.05.1990; Elsevier
• Subjects: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid - analogs & derivatives; 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid - pharmacology; Acetates - pharmacology; Adenoma, Islet Cell - metabolism; Ammonium Chloride - pharmacology; Bicarbonates - pharmacology; Biological and medical sciences; Carrier Proteins - metabolism; Cell physiology; Chlorides - pharmacology; Fluoresceins; Fluorescent Dyes; Fundamental and applied biological sciences. Psychology; HCO −3/Cl − exchange; Hydrogen-Ion Concentration; Insulin - metabolism; Insulin Secretion; Insulin-secreting cell; Insulinoma - metabolism; Intracellular pH, Na +/H + exchange; Lactates - pharmacology; Lactic Acid; Membrane and intracellular transports; Molecular and cellular biology; Pancreatic Neoplasms - metabolism; Sodium-Hydrogen Exchangers; Tumor Cells, Cultured; HCO − 3/Cl − exchange; Insulin-secreting cell; Intracellular pH, Na +/H + exchange; Regulation(control); Cell line; Sodium; Insulinoma; Acidification; PH; Proton; Coupled transport; Intracellular; Ion exchange
• ISSN: 0303-7207; 1872-8057
• DOI: 10.1016/0303-7207(90)90070-O

The addition of glucose to suspensions of HIT-T15 insulinoma cells caused a small, transient acidification followed by a gradual, progressive alkalinisation, as assessed by the fluorescent pH-sensitive dye 2',7'-biscarboxyethyl-5'-(6')-carboxyfluorescein (BCECF). Treatment of cells with acetate or lactate produced an immediate, marked acidification followed by recovery and a subsequent alkalinisation. In contrast, addition of NH 4C1 caused a rapid rise in intracellular pH (pHi) and recovery to resting values. In cells where Na +/H + exchange was inhibited, either with amiloride or by omission of Na + from the medium, glucose caused a progressive acidification, whilst recovery from acetate- or lactate-induced acidification was prevented. Under sodium-free conditions, recovery from acidification could be initiated by addition of Na +. Inhibition of HCO 3 −/C1 − exchange by pretreatment with 4,4'-diisothiocyanatostilbene 2,2'-disulphonic acid (DIDS), or by omission of HCO 3 − or Cl − from the medium did not affect any of the changes in pHi elicited by the above agents. It is concluded that the principal mechanism responsible for pHi regulation in HIT-T15 cells is the Na +/H + antiporter and that the HCO 3 −/C1 − exchange systems make little, if any, contribution.