Effect of Gabexate Mesylate (FOY), a Drug for Serine Proteinase-Mediated Diseases, on the Nitric Oxide Pathway

Abstract

Considering the structural similarity between gabexate mesylate (FOY), a drug for serine proteinase-mediated diseases, and L-arginine, the effect of gabexate mesylate on the nitric oxide (NO) pathway has been investigated. Gabexate mesylate inhibits competitively constitutive and inducible NO synthase (cNOS and iNOS, respectively), with Kivalues of 1.0×10−4M and 5.0×10−3M, respectively, at pH 7.4 and 37.0°C. However, gabexate mesylate is not an NO precursor. Moreover, like other NOS inhibitors, gabexate mesylate increases iNOS mRNA expression in rat C6 glioma cells, as induced byE. colilipopolysaccharide plus interferon-γ. Finally, gabexate mesylate inhibits dose-dependently nitrite production (i.e. NO release) in rat C6 glioma cells, as induced byE. colilipopolysaccharide plus interferon-γ. Thus, this drug should be administered under careful control, since enzyme inhibition may occur alsoin vivo.