Figure 5.

PKC downregulation by 6 h pretreatment with phorbol esters inhibits iNOS protein expression and NO production in J774 cells. (a) J774 cells were pretreated with PMA (1 μM) or vehicle for 6 h before stimulation by LPS (10 ng ml⁻¹). After 24 h incubation, nitrite concentrations in the culture medium were measured as a marker of NO production. Values are mean±s.e.m. (n=6). (b) J774 cells were pretreated with PMA (1 μM), PDD (1 μM) or vehicle for 6 h before stimulation by LPS (10 ng ml⁻¹). After 24 h, incubations were terminated and immunoblots were run using antibody against iNOS. Chemiluminescent signal was quantified as described under the Methods section. Values are mean±s.e.m. (n=3). ^**P<0.01 as compared with cells treated with LPS.