Fig. 1.

Fluid shear stress (FSS) induces prostaglandin E₂ (PGE₂) secretion into the media bathing cultured inner medullary collecting duct type 3 (IMCD3; A) and mpk cortical collecting duct (mpkCCD; B) cells and this response in IMCD3 cells is inhibited equally by cyclooxygenase (COX)-1 or COX-2 inhibitors (C). IMCD3 and mpkCCD cells were grown to confluence and exposed to 0.4 dyn/cm² of FSS or maintained under static condition for 2 h. Cells were incubated in culture media for 1 h, the conditioned media were collected, and PGE₂ concentrations (pg/ml) were measured by enzyme immunoassay. The PGE₂ concentration was normalized to the amount of cellular protein (pg·ml⁻¹·μg⁻¹) present on the slide. Sheared IMCD3 (A) and mpkCCD (B) cells released more PGE₂ than their respective static controls. Inhibitors of COX-1 (100 nM SC560) or COX-2 (1 μM CAY10404) reduced FSS-induced PGE₂ release by 62.0 ± 8.4% (*P < 0.05) and 70.0 ± 2.7% (*P < 0.05) compared with the shear-untreated IMCD3 cells, respectively (C). PGE₂ concentration remained greater than static control (#P < 0.05).