In vitro induction of nitric oxide by fructose-1,6-diphosphate in the cardiovascular system of rats.

Nitric oxide (NO) functions as a cellular messenger in a number of organs and cell systems in the cardiovascular system (CVS); it is a significant determinant of basal vascular tone and regulates myocardial contractility and platelet aggregation. The present study focused upon understanding the in vitro effects of fructose-1,6-diphosphate (FDP) on the rat cellular NO pathway. The iNOS activity was measured by monitoring the formation of (3H)-citrulline in 50,000 g soluble fractions of crude homogenates of endothelial (ET) and smooth muscle cells (SMC) from the arteries of rats, and macrophages (MAC) and lymphocytes (LYM) from rat blood. FDP in concentrations of 10-1000 microM stimulated rat cellular iNOS activity in a concentration-dependent manner. FDP-stimulated rat cellular iNOS was found to be completely reversed by 5 microM concentration of NG-monomethyl-L-arginine (L-NMMA), the potent mammalian NOS inhibitor. These studies demonstrated that FDP may induce the formation of NO by stimulating rat cardiovascular iNOS activity.