Inhibition of the Na+/H(+)-antiporter by theophylline in growth-arrested monkey kidney cells.

Treatment of monkey kidney CV-1 cells with theophylline leads to growth arrest, with sensitivity to theophylline being greatly increased in the absence of bicarbonate. Theophylline, like amiloride, increases the sensitivity of cells to intracellular acidification and protects cells from acid shock. These observations and direct measurements of 22Na uptake suggest that growth-arresting effects of theophylline are mediated by the Na+/H(+)-antiporter.