Glucose and pyruvate regulate cytokine-induced nitric oxide production by cardiac myocytes

Abstract

Metabolic requirements for the production of nitric oxide (NO) by cytokine-stimulated neonatal rat cardiac myocytes (CM) were studied. CM were cultured for 48 h in media containing interleukin-1 beta (IL-1 beta) and free fatty acids. Removal of glucose from the media partially inhibited 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 inhibited IL-1 beta-stimulated NO2- production [0.7 +/- 0.5 nmol.(1.25 X 10(5) cells)-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 enhance NO2- production in the presence or absence of glucose (n = 12). The inactive analogue 3-O-methylglucose had no effect on NO2- production (n = 12). Reverse transcription-polymerase chain reaction revealed that pyruvate blocked 2-DG inhibition of inducible NO synthase mRNA expression. 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 glycolytic end product pyruvate.