In renal A6 cells, basal Na⁺ transport is regulated by PI-3-Kinase (Blazer-Yost et al. 1998, Paunescu et al. 2000, Record et al. 1998). This study aims to identify the role of PI-3-Kinase in the regulation of dexamethasone (dex) induced Na⁺ transport in bronchiolar H441 cells, and to investigate whether forskolin regulates Na⁺ transport via a pathway dependent upon PI-3-Kinase. H441 cells were cultured in insulin free RPMI medium. On reaching confluence, cells were seeded onto Snapwell inserts (~0.5 x 10^-6 cells per insert). After 24 hours medium was removed and basolateral medium was replaced with insulin free RPMI medium prepared using dialysed serum and containing dex (200nM) as the only hormone. The cells were grown at apical air interface for 8 days before being mounted in Ussing chambers. The basal short circuit current (I_sc of monolayers was 33.08 ± 3.01μAcm^-2 (n=7 all data shown as mean ± SEM) with transepithelial resistance (R_t of 214.51 ± 9.13 Ωcm^-2 (n=7). This I_sc value is similar to that seen in H441 cells cultured in the presence of insulin 37.0 ± 2.8 μAcm^-2 (n=7) (Ramminger et al. 2004) indicating that, in contrast to A6 cells, insulin is not required to regulate dex induced Na⁺ transport. However, addition of the PI-3-Kinase inhibitor LY294002 (LY, 50μM) inhibited I_sc by 61.6 ± 4.4% after 55 mins). The addition of forskolin (10μM) stimulated I_sc with a peak (133.3 ± 15.9%) reached after ~20 mins, an effect which was still present when added 10 mins after LY. The amiloride sensitive I_sc (AS-I_sc) of monolayers receiving no drug treatment was 24.07 ± 3.07μA cm^-2 (n=7). The addition of forskolin increased AS-I_sc to 35.37 ± 6.18μA cm^-2 (ΔI_sc 11.30 ± 4.07μAcm^-2 P<0.05 n=7) while addition of LY reduced AS-I_sc to 11.73 ± 2.81μAcm^-2 (ΔI_sc -12.37 ± 2.77μAcm^-2 P<0.05 n=7). The addition of forskolin after LY increased AS-I_sc to 33.10 ± 5.51 μAcm^-2 (n=7 data analysed using Repeated measures ANOVA with Bonferroni Post-Hoc Test). These data suggest that PI-3-Kinase maintains dexamethasone induced Na⁺ transport in H441 cells, but, in contrast to that seen in renal A6 cells, insulin is not required to maintain the activity of this enzyme. Since inhibition of PI-3-Kinase does not block the response to forskolin it is likely that forskolin regulates Na+ transport via an independent pathway.