Testosterone and Cyclooxygenases Modulate Ion Transport in Vas Deferens Epithelia.

Abstract

Epithelial cells lining the rat vas deferens express cyclooxygenase (COX) 2 in a testosterone-dependent fashion although no functional role for this expression pattern has been established. It was hypothesized that testosterone modulates anion secretion across vas deferens epithelia via COX-dependent pathways and prostaglandin (PG) synthesis. Vas deferens epithelial cells were isolated from porcine tissues and cultured as monolayers on permeable supports within paired conditions until assayed in modified Ussing chambers. RNA and protein were isolated concurrently for semi-quantitative expression analysis. Native porcine vas deferens was subjected to immunocytochemistry. Testosterone-treated monolayers exhibited bradykinin (BK)-induced ion transport (measured as short circuit current) 65% greater than paired vehicle-treated monolayers. The non-selective COX inhibitor indomethacin inhibited (80% less) anion secretion stimulated by BK. qRT-PCR revealed a modest testosterone induced upregulation in COX-2 mRNA and this transcript was 20 times more abundant than its counterpart COX-1. Immunocytochemistry performed to label the bradykinin 2 receptor subtype (B2R), and the prostanoid receptors EP2 and EP4 support that these receptors are localized at the apical membrane of porcine vas deferens epithelium. Taken together, these results suggest that testosterone plays a key permissive role for BK-stimulated anion secretion. BK acts at the B2R receptor to increase COX activity and the synthesis of PGs that ultimately bind to EP receptors to increase cAMP levels and initiate and/or intensify anion secretion into the vas deferens luminal environment to which sperm is exposed. [Supported by the Cystic Fibrosis Foundation (SCHULT06PO) and the NIH (RR-17686)].