GLUCOSE AND PYRUVATE REGULATE CYTOKINE-INDUCED NITRIC-OXIDE PRODUCTION BY CARDIAC MYOCYTES

Metabolic requirements for the production of nitric oxide (NO) by cyto kine-stimulated neonatal rat cardiac myocytes (CM) were studied. CM we re cultured for 48 h in media containing interleukin-1 beta (IL-1 beta ) and free fatty acids. Removal of glucose from the media partially in hibited IL-1 beta-stimulated nitrite (NO2-) production [8.1+/-0.3 vs. 4.4+/-0.6 nmol .(1.25 x 10(5) cells)(-1). 48 h(-1); P < 0.01; n = 12]. The glycolytic inhibitor 2-deoxy-D-glucose (2-DG) completely inhibite d IL-1 beta-stimulated NO; production [0.7+/-0.5 nmol (1.25x10(5) cell s)(-1). 48 h(-1); P<0.01; n = 12]. The addition of the glycolytic end product, pyruvate, completely blocked the 2-DG inhibition of IL-1 beta -stimulated NO2- production [7.4+/-0.4 nmol .(1.25 x 10(5) cells)(-1). 48 h(-1); P < 0.01; n = 12]. Pyruvate alone did not significantly enh ance NO, production in the presence or absence of glucose (n = 12). Th e inactive analogue 3-O-methylglucose had no effect on NO, production (n = 12). Reverse transcription-polymerase chain reaction revealed tha t pyruvate blocked 2-DG inhibition of inducible NO synthase mRNA expre ssion. Neither 2-DG nor pyruvate had any effect on GTP-cyclohydrolase I mRNA expression in CM. We report for the first time that optimal IL- 1 beta-stimulated NO production by CM requires both glucose and the gl ycolytic end product pyruvate.