Expression of aquaporin-1 mRNA and protein in polymorphonuclear granulocytes is induced by lipopolysaccharide. Polymorphonuclear granulocytes (PMNs) isolated from healthy blood donor volunteers were incubated for 3 hours at 37°C in six-well plates with plain cell-culture medium (ctr) or lipopolysaccharide (LPS) from Pseudomonas aeruginosa in the absence or presence of NF-κB inhibitor EF-24. (A) Representative expression of aquaporin-1 (Aqp1; upper panel) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH; lower panel) mRNAs. End-point PCR was performed on RNA isolated from PMNs, as above and analyzed on 2.5% agarose gel. (B) Fold-increase of Aqp1 gene expression, as measured by real-time PCR in PMNs. (C) Increase in protein expression of Aqp1 in crude protein samples isolated from PMNs, as analyzed by SDS-PAGE and immunoblotting. Relative Aqp1 protein expression was estimated by densitometry using β-tubulin as a loading control. **P <0.01 from corresponding control. #P <0.05 from corresponding LPS treatment by one-way analysis of variance followed by Newman–Keuls multiple comparison test.