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STUDY ON REGULATION MECHANISM OF PROSTACYCLIN SYNTHESIS BY SELENIUM
Objective:
To evaluate the regulation mechanism of prostacyclin(PGI 2) synthesis by selenium (Se). Methods:Male
Wistar rats were fed Se deficient diet, Se supplemented diet and stock diet for 14 weeks respectively. The levels of Se, PGI 2, TXA 2 and lipid peroxide (LPO), and activities of glutathione peroxidase (GSH Px), prostaglandin endoperoxide synthase peroxidase (PGHS Px) in blood and some tissues were determined. The predicted secondary structures of 3untranslated region (UTR) of 3 PGI 2 synthase genes (human, bovine and rat) were compared with the selenoproteine insertion sequences(SECIS) elements in 3UTR of 39 well known selenoprotein genes by computer RNA folding program. Rusults: The plasma PGI 2, Se and GSH Px activity in blood and liver of Se deficient rats were decreased significantly. LPO in plasma and liver were increased significantly, but no remarkable differences in plasma TXA 2 and tissue PGHS Px activities. The specific SECIS element belonging to selenoprotein gene was not found in 3UTR of PGI 2 synthase mRNAs. Conclusion: PGI 2 synthase may not be a selenoenzyme. The regulation of PGI 2 synthesis by Se may be due to inhibited lipid peroxidation by GSH Px or/and other selenoprotein.
Published: March 20, 2000
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