Glucose modulation of aldose reductase mRNA expression and its activity in cultured calf pulmonary artery endothelial cells

Abstract

We examined the effect of glucose on aldose reductase mRNA expression and its activity in calf pulmonary artery endothelial cells. After the cells were exposed to 18 mmol/l glucose, aldose reductase mRNA expression began to increase at 6 h, reached a maximum (about 2.4-fold increase) at 12 h, and thereafter gradually decreased. Aldose reductase activity was found to strongly correlate with aldose reductase mRNA expression after cells were exposed to 18 mmol/l glucose. In contrast, aldose reductase mRNA expression was significantly decreased following exposure to 55 mmol/l glucose. Aldose reductase activity was also decreased at 24 h after 55 mmol/l glucose. The increase in aldose reductase mRNA level caused by glucose was inhibited by 1 microgram/ml of actinomycin D. These phenomena appear to be glucose-specific since neither 3-O-methylglucose nor fructose affected the levels of aldose reductase mRNA. We clearly demonstrate that aldose reductase mRNA level and its activity are modulated by glucose in calf pulmonary artery endothelial cells. Our data suggest that activation of aldose reductase in endothelial cells may contribute to the development of diabetic macroangiopathy.