Chemical hypoxia-induced glucose transporter-4 translocation in neonatal rat cardiomyocytes.

ABSTRACT

BACKGROUND: AMP-activated protein kinase (AMPK) activation plays an essential role in glucose metabolism of the heart. This study aimed at investigating whether AMPK was involved in glucose transporter-4 (GLUT-4) translocation induced by azide-induced chemical hypoxia in primary cultured neonatal rat cardiomyocytes. METHODS: With or without adenine 9-beta-D-arabinofuranoside (ara A, AMPK inhibitor) preincubation, primary cultured rat cardiomyocytes were randomized to several groups as incubated with azide (the respiratory chain inhibitor), insulin, or 5-aminoimidazole-4-carboxyamide-1-beta-D-ribofuranoside (AICAR, an AMPK activator). Glucose uptake was measured through gamma-scintillation and GLUT-4 protein was detected by Western blot for each group. RESULTS: Azide-induced chemical hypoxia and AICAR both increased glucose uptake and GLUT-4 translocation in cardiomyocytes, and AICAR had an additive effect on insulin action. Ara A decreased AICAR- and azide-induced glucose uptake and GLUT-4 translocation but did not affect basal or insulin-stimulated glucose uptake. CONCLUSIONS: Azide-induced chemical hypoxia increased glucose uptake and GLUT-4 translocation in neonatal rat cardiomyocytes through a mechanism that at least was partially mediated by AMPK activation.