Forskolin, UTP, 1-ethyl-2-benzimidazolinone (1-EBIO), NS004, 8-methoxypsoralen (Methoxsalen; 8-MOP), and genistein were evaluated for their effects on ion transport across primary cultures of human bronchial epithelium (HBE) expressing wild-type (wt HBE) and ΔF508 (ΔF-HBE) cystic fibrosis transmembrane conductance regulator. In wt HBE, the baseline short-circuit current (I _sc) averaged 27.0 ± 0.6 μA/cm² (n = 350). Amiloride reduced this I _sc by 13.5 ± 0.5 μA/cm² (n = 317). In ΔF-HBE, baseline I _sc was 33.8 ± 1.2 μA/cm² (n = 200), and amiloride reduced this by 29.6 ± 1.5 μA/cm² (n = 116), demonstrating the characteristic hyperabsorption of Na⁺ associated with cystic fibrosis (CF). In wt HBE, subsequent to amiloride, forskolin induced a sustained, bumetanide-sensitive I _sc(ΔI _sc = 8.4 ± 0.8 μA/cm²; n = 119). Addition of acetazolamide, 5-(N-ethyl-N-isopropyl)-amiloride, and serosal 4,4′-dinitrostilben-2,2′-disulfonic acid further reducedI _sc, suggesting forskolin also stimulates HCO₃ ⁻ secretion. This was confirmed by ion substitution studies. The forskolin-induced I _scwas inhibited by 293B, Ba²⁺, clofilium, and quinine, whereas charybdotoxin was without effect. In ΔF-HBE the forskolinI _sc response was reduced to 1.2 ± 0.3 μA/cm² (n = 30). In wt HBE, mucosal UTP induced a transient increase in I _sc (ΔI _sc = 15.5 ± 1.1 μA/cm²;n = 44) followed by a sustained plateau, whereas in ΔF-HBE the increase in I _sc was reduced to 5.8 ± 0.7 μA/cm² (n = 13). In wt HBE, 1-EBIO, NS004, 8-MOP, and genistein increasedI _sc by 11.6 ± 0.9 (n = 20), 10.8 ± 1.7 (n = 18), 10.0 ± 1.6 (n = 5), and 7.9 ± 0.8 μA/cm²(n = 17), respectively. In ΔF-HBE, 1-EBIO, NS004, and 8-MOP failed to stimulate Cl⁻ secretion. However, addition of NS004 subsequent to forskolin induced a sustained Cl⁻secretory response (2.1 ± 0.3 μA/cm²,n = 21). In ΔF-HBE, genistein alone stimulated Cl⁻ secretion (2.5 ± 0.5 μA/cm²,n = 11). After incubation of ΔF-HBE at 26°C for 24 h, the responses to 1-EBIO, NS004, and genistein were all potentiated. 1-EBIO and genistein increased Na⁺ absorption across ΔF-HBE, whereas NS004 and 8-MOP had no effect. Finally, Ca²⁺-, but not cAMP-mediated agonists, stimulated K⁺ secretion across both wt HBE and ΔF-HBE in a glibenclamide-dependent fashion. Our results demonstrate that pharmacological agents directed at both basolateral K⁺ and apical Cl⁻ conductances directly modulate Cl⁻secretion across HBE, indicating they may be useful in ameliorating the ion transport defect associated with CF.