Prostaglandins (PGs), particularly PGE(2), have been implicated in the control of testicular steroidogenesis, spermatogenesis, and local immunity. However, virtually nothing is known about the expression or activity of the prostaglandin-endoperoxide synthases (PTGSs; also referred to as the cyclooxygenases), the specific rate-limiting enzymes responsible for PG production, in the adult testis. This activity was investigated in rats under normal conditions and during lipopolysaccharide-induced inflammation using quantitative real-time PCR, in situ hybridization, Western blotting, and PGE(2) measurements by ELISA. The mRNA for both the "constitutive" Ptgs1 and the "inducible" Ptgs2 forms was detected in multiple testicular cell types. Testicular Ptgs2 expression was substantially higher than that of Ptgs1, and testicular production of PGE(2) in vitro was found to be suppressed by a specific PTGS2 inhibitor (NS-398), but not by an inhibitor of PTGS1. Further investigation indicated that 1) PGE(2) production in the adult testis is attributable to constitutive expression of PTGS2 by somatic (Leydig cells and Sertoli cells) and spermatogenic cells; 2) testicular macrophages constitutively produce relatively low levels of PTGS2 and PGE(2) but are the only cell type to respond significantly to an inflammatory stimulus by increasing production of PGE(2); and 3) testicular PTGS2 expression and intratesticular PGE(2) levels are only marginally affected by acute inflammation. These data point toward a previously unanticipated maintenance role for the "inducible" PTGS2 enzyme in normal testicular function, as well as an anomalous response of testicular PTGS2 to inflammatory stimuli. Both observations are consistent with the reduced capacity of the testis to initiate and support inflammatory reactions.

Background and Purpose-We have previously identified an increased susceptibility of Gpx1 Ϫ/Ϫ mice to increased infarct size after middle cerebral artery occlusion (MCAO). This study was designed to elucidate the mechanisms involved in elevated neuronal cell death arising from an altered endogenous oxidant state. Methods-Gpx1Ϫ/Ϫ mice were exposed to transient MCAO and reperfusion by intraluminal suture blockade. Protein expression of the p65 subunit of transcription factor nuclear factor-B (NF-B) was examined by immunohistochemistry and Western Analysis. NF-B DNA-protein activity was assessed by electrophoretic mobility shift assays (EMSA). Wild-type and Gpx1Ϫ/Ϫ mice were exposed to MCAO with or without the NF-B inhibitor, pyrrolidinedithiocarbamate (PDTC). Results-Upregulation of the p65 subunit of NF-B and subsequent p65 phosphorylation at serine 536 was detected in the Gpx1 Ϫ/Ϫ brains after stroke. EMSAs revealed that increased ischemia-enhanced DNA binding of NF-B was observed in Gpx1Ϫ/Ϫ mice compared with wild-type. Supershift assays indicated that the p50 and p65 subunits participated in the bound NF-B complex. The NF-B inhibitor PDTC, a potential antioxidant, was able to afford partial neuroprotection in the Gpx1 Ϫ/Ϫ mice. Conclusions-NF-B is upregulated in the Gpx1Ϫ/Ϫ mouse, and this upregulation contributes to the increased cell death seen in the Gpx1 Ϫ/Ϫ after MCAO. The activation of NF-B may increase the expression of downstream target genes that are involved in the progression of neural injury after MCAO.