Effects of BPS on intracellular cAMP production during hypoxia. Cultured HPASMC were exposed to 21% or 2% oxygen in the presence or absence of 10 μM of BPS for indicated periods. Concentrations of cAMP in cell lysates were measured using low-pH cAMP ELISA kits. Although BPS significantly induced cAMP expression, intracellular cAMP expression did not significantly differ between the indicated oxygen concentrations. Line with solid circles, 21% oxygen; dotted line with open circles, 2% oxygen. Data are expressed as means ± SE (n = 6).